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Aldehyde dehydrogenase-2 deficiency (ALDH2∗2) found in 36 % of Han Chinese, affects approximately 8 % of the world population. ALDH2 is a mitochondrial key enzyme in detoxifying reactive aldehydes to less reactive forms. Studies demonstrate a potential link between ALDH2∗2 mutation and neurodegenerative diseases. Multiple sclerosis (MS) is an incurable and disabling neurodegenerative autoimmune disease that induces motor, and cognitive impairment, and hypersensitivity, including chronic pain. Accumulating evidence suggests that reactive aldehydes, such as 4-hydroxynonenal (4-HNE), contribute to MS pathogenesis. Here, using knock-in mice carrying the inactivating point mutation in ALDH2, identical to the mutation found in Han Chinese, we showed that the impairment in ALDH2 activity heightens motor disabilities, and hypernociception induced by experimental autoimmune encephalomyelitis (EAE). The deleterious clinical signs are followed by glial cell activation in the spinal cord and increased 4-HNE levels in the spinal cord and serum. Importantly, the pharmacological ALDH2 activation by Alda-1 ameliorates EAE-induced hypernociception and motor impairment in both wild-type and ALDH2∗2KI mice. Reduced hypernociception was associated with less early growth response protein 1 (EGR1), neuronal and glial activation, and reactive aldehyde accumulation in the spinal cord and serum. Taken together, our data suggest that the mitochondrial enzyme ALDH2 plays a role in regulating clinical, cellular, and molecular responses associated with EAE. This indicates that ALDH2 could serve as a molecular target for MS control, with ALDH2 activators, like Alda-1 as potential neuroprotective candidates. Furthermore, ALDH2∗2 carriers may be at increased risk of developing more accentuated MS symptoms., Competing Interests: Declaration of competing interest Vanessa Olzon Zambelli is named inventor of patents related to Alda-1., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objectives: Bisphosphonates (BFs) show clinical effectiveness in managing osteoporosis and bone metastases but pose risks of bisphosphonate-related jaw osteonecrosis (BRONJ). With no established gold standard for BRONJ treatment, our focus is on symptom severity reduction. We aimed to assess the preventive effects of bioactive glass and/or pericardial membrane in a preclinical BRONJ model, evaluating their potential to prevent osteonecrosis and bone loss post-tooth extractions in zoledronic acid (ZA)-treated animals., Methods: Rats, receiving ZA or saline biweekly for four weeks, underwent 1st and 2nd lower left molar extractions. Pericardial membrane alone or with F18 bioglass was applied post-extractions. Microarchitecture analysis and bone loss assessment utilized computerized microtomography (CT) and positron emission tomography (PET) with 18F-FDG and 18F-NaF tracers. Histological analysis evaluated bone injury., Results: Exclusive alveolar bone loss occurred post-extraction in the continuous ZA group, inducing osteonecrosis, osteolysis, osteomyelitis, and abscess formation. Concurrent pericardial membrane with F18 bioglass application prevented these outcomes. Baseline PET/CT scans showed no discernible uptake differences, but post-extraction 18F-FDG tracer imaging revealed heightened glucose metabolism at the extraction site in the ZA-treated group with membrane, contrasting the control group., Conclusion: These findings suggest pericardial membrane with F18 bioglass effectively prevents BRONJ in the preclinical model., Competing Interests: The authors declare the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Pellicano, Benites, Paschoa, Oliveira, Campos, Martins, Real, de Paula Faria, Fonseca, Martinez, Pagano and Fregnani.)

Maladaptive avoidance behaviour is often observed in patients suffering from anxiety and trauma- and stressor-related disorders. The prefrontal-amygdala-hippocampus network is implicated in learning and memory consolidation. Neuroinflammation in this circuitry alters network dynamics, resulting in maladaptive avoidance behaviour. The two-way active avoidance test is a well-established translational model for assessing avoidance responses to stressful situations. While some animals learn the task and show adaptive avoidance (AA), others show strong fear responses to the test environment and maladaptive avoidance (MA). Here, we investigated if a distinct neuroinflammation pattern in the prefrontal-amygdala-hippocampus network underlies the behavioural difference observed in these animals. Wistar rats were tested 8 times and categorized as AA or MA based on behaviour. Brain recovery followed for the analysis of neuroinflammatory markers in this network. AA and MA presented distinct patterns of neuroinflammation, with MA showing increased astrocyte, EAAT-2, IL-1β, IL-17 and TNF-ɑ in the amygdala. This neuroinflammatory pattern may underlie these animals' fear response and maladaptive avoidance. Further studies are warranted to determine the specific contributions of each inflammatory factor, as well as the possibility of treating maladaptive avoidance behaviour in patients with psychiatric disorders with anti-inflammatory drugs targeting the amygdala., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Accidents caused by Bothrops jararaca (Bj) snakes result in several local and systemic manifestations, with pain being a fundamental characteristic. The inflammatory process responsible for hyperalgesia induced by Bj venom (Bjv) has been studied; however, the specific roles played by the peripheral and central nervous systems in this phenomenon remain unclear. To clarify this, we induced hyperalgesia in rats using Bjv and collected tissues from dorsal root ganglia (DRGs) and spinal cord (SC) at 2 and 4 h post-induction. Samples were labeled for Iba-1 (macrophage and microglia), GFAP (satellite cells and astrocytes), EGR1 (neurons), and NK1 receptors. Additionally, we investigated the impact of minocycline, an inhibitor of microglia, and GR82334 antagonist on Bjv-induced hyperalgesia. Our findings reveal an increase in Iba1 in DRG at 2 h and EGR1 at 4 h. In the SC, markers for microglia, astrocytes, neurons, and NK1 receptors exhibited increased expression after 2 h, with EGR1 continuing to rise at 4 h. Minocycline and GR82334 inhibited venom-induced hyperalgesia, highlighting the crucial roles of microglia and NK1 receptors in this phenomenon. Our results suggest that the hyperalgesic effects of Bjv involve the participation of microglial and astrocytic cells, in addition to the activation of NK1 receptors.

Pain control after deep brain stimulation (DBS) in Parkinson's disease (PD) remains unclear. Following six months, subthalamic (STN)-DBS reduced sensory complaints related to parkinsonism and bodily discomfort, increasing central beta-endorphin level. Pallidal GPi-DBS decreased bodily discomfort and beta-endorphin levels. Unexplained pain by other conditions and bodily discomfort were negatively correlated with beta-endorphin levels. Thus, DBS regulates central opioids, and prioritizing STN is important for PD patients with significant sensory complications., (© 2024. The Author(s).)

Deep brain stimulation has revolutionized the treatment of movement disorders and is gaining momentum in the treatment of several other neuropsychiatric disorders. In almost all applications of this therapy, the insertion of electrodes into the target has been shown to induce some degree of clinical improvement prior to stimulation onset. Disregarding this phenomenon, commonly referred to as 'insertional effect', can lead to biased results in clinical trials, as patients receiving sham stimulation may still experience some degree of symptom amelioration. Similar to the clinical scenario, an improvement in behavioural performance following electrode implantation has also been reported in preclinical models. From a neurohistopathologic perspective, the insertion of electrodes into the brain causes an initial trauma and inflammatory response, the activation of astrocytes, a focal release of gliotransmitters, the hyperexcitability of neurons in the vicinity of the implants, as well as neuroplastic and circuitry changes at a distance from the target. Taken together, it would appear that electrode insertion is not an inert process, but rather triggers a cascade of biological processes, and, as such, should be considered alongside the active delivery of stimulation as an active part of the deep brain stimulation therapy., Competing Interests: The authors report no competing interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Treatment-resistant depression (TRD) is a debilitating condition that affects millions of individuals worldwide. Deep brain stimulation (DBS) has been widely used with excellent outcomes in neurological disorders such as Parkinson's disease, tremor, and dystonia. More recently, DBS has been proposed as an adjuvant therapy for TRD. To date, the antidepressant efficacy of DBS is still controversial, and its mechanisms of action remain poorly understood. Astrocytes are the most abundant cells in the nervous system. Once believed to be a "supporting" element for neuronal function, astrocytes are now recognized to play a major role in brain homeostasis, neuroinflammation and neuroplasticity. Because of its many roles in complex multi-factorial disorders, including TRD, understanding the effect of DBS on astrocytes is pivotal to improve our knowledge about the antidepressant effects of this therapy. In depression, the number of astrocytes and the expression of astrocytic markers are decreased. One of the potential consequences of this reduced astrocytic function is the development of aberrant glutamatergic neurotransmission, which has been documented in several models of depression-like behavior. Evidence from preclinical work suggests that DBS may directly influence astrocytic activity, modulating the release of gliotransmitters, reducing neuroinflammation, and altering structural tissue organization. Compelling evidence for an involvement of astrocytes in potential mechanisms of DBS derive from studies suggesting that pharmacological lesions or the inhibition of these cells abolishes the antidepressant-like effect of DBS. In this review, we summarize preclinical data suggesting that the modulation of astrocytes may be an important mechanism for the antidepressant-like effects of DBS., Competing Interests: Declaration of Competing Interest The authors declare no competing interests related to this work., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Conventional thoracotomy (CT) often leads to systemic inflammatory response syndrome (SIRS), which induces several clinical complications. CT remains widely used in low-income institutions. Although minimally invasive surgical procedures, such as robotic surgery (RS), have been used to prevent many of the complications inherit from the surgical procedure. Here, we investigated the protective effect of vagus nerve stimulation (VNS) in a pre-clinical model during CT or RS and postoperative period (POP) relative to clinical complications and inflammatory control. The objective was to compare hemodynamic features and cytokine levels in the blood, lung, and bronchoalveolar lavage (BAL) fluids of animals subjected to CT or RS with or without VNS., Methods: Twenty-four minipigs were subjected to 12 animals CT and 12 animals RS, with or without VNS, and accompanied 24 h later by pulmonary lobectomy. Blood samples for evaluating the hemodynamic parameters were collected before the surgical preparation, immediately after the beginning of VNS, and every 4 h until 24 h after the lobectomy. BAL fluid and lung tissue were collected at the end of the experiment. Cytokine levels were evaluated in the blood, BAL fluid, and lung tissues., Results: VNS maintained a more stable heart rate during POP and decreased the incidence of overall cardiac complications while preventing increase in IL-6 levels 12 h after lobectomy, compared to sham animals. No differences were found in cytokine expression in the BAL fluid and lung tissue in any of the studied groups., Conclusions: Taken together, our data suggested that VNS should be considered a non-pharmacological tool in the prevention of the exacerbated inflammatory response responsible for severe clinical complications, especially in more aggressive surgical procedures., Competing Interests: Conflicts of Interest:All authors have completed the ICMJE uniform disclosure form (available at https://atm.amegroups.com/article/view/10.21037/atm-22-2919/coif). RMT serves as a speaker/proctor for Medtronic, Strattner/Intuitive, AstraZeneca, MSD, BMS. The other authors have no conflicts of interest to declare., (2023 Annals of Translational Medicine. All rights reserved.)

Understanding the mechanisms responsible for anxiety disorders is a major challenge. Avoidance behavior is an essential feature of anxiety disorders. The two-way avoidance test is a preclinical model with two distinct subpopulations-the good and poor performers-based on the number of avoidance responses presented during testing. It is believed that the habenula subnuclei could be important for the elaboration of avoidance response with a distinct pattern of activation and neuroinflammation. The present study aimed to shed light on the habenula subnuclei signature in avoidance behavior, evaluating the pattern of neuronal activation using FOS expression and astrocyte density using GFAP immunoreactivity, and comparing control, good and poor performers. Our results showed that good performers had a decrease in FOS immunoreactivity (IR) in the superior part of the medial division of habenula (MHbS) and an increase in the marginal part of the lateral subdivision of lateral habenula (LHbLMg). Poor performers showed an increase in FOS in the basal part of the lateral subdivision of lateral habenula (LHbLB). Considering the astroglial immunoreactivity, the poor performers showed an increase in GFAP-IR in the inferior portion of the medial complex (MHbl), while the good performers showed a decrease in the oval part of the lateral part of the lateral complex (LHbLO) in comparison with the other groups. Taken together, our data suggest that specific subdivisions of the MHb and LHb have different activation patterns and astroglial immunoreactivity in good and poor performers. This study could contribute to understanding the neurobiological mechanisms responsible for anxiety disorders.

Norepinephrine plays an important role in modulating memory through its beta-adrenergic receptors (Adrβ: β 1 , β 2 and β 3 ). Here, we hypothesized that multisensory stimulation would reverse memory impairment caused by the inactivation of Adrβ 3 (Adrβ 3 KO) with consequent inhibition of sustained glial-mediated inflammation. To test this, 21- and 86-day-old Adrβ 3 KO mice were exposed to an 8-week multisensory stimulation (MS) protocol that comprised gustatory and olfactory stimuli of positive and negative valence; intellectual challenges to reach food; the use of hidden objects; and the presentation of food in ways that prompted foraging, which was followed by analysis of GFAP, Iba-1 and EAAT2 protein expression in the hippocampus (HC) and amygdala (AMY). The MS protocol reduced GFAP and Iba-1 expression in the HC of young mice but not in older mice. While this protocol restored memory impairment when applied to Adrβ 3 KO animals immediately after weaning, it had no effect when applied to adult animals. In fact, we observed that aging worsened the memory of Adrβ 3 KO mice. In the AMY of Adrβ3KO older mice, we observed an increase in GFAP and EAAT2 expression when compared to wild-type (WT) mice that MS was unable to reduce. These results suggest that a richer and more diverse environment helps to correct memory impairment when applied immediately after weaning in Adrβ 3 KO animals and indicates that the control of neuroinflammation mediates this response.

Epidural motor cortex stimulation (MCS) is an effective treatment for refractory neuropathic pain; however, some individuals are unresponsive. In this study, we correlated the effectiveness of MCS and refractoriness with the expression of cytokines, neurotrophins, and nociceptive mediators in the dorsal root ganglion (DRG), sciatic nerve, and plasma of rats with sciatic neuropathy. MCS inhibited hyperalgesia and allodynia in two-thirds of the animals (responsive group), and one-third did not respond (refractory group). Chronic constriction injury (CCI) increased IL-1β in the nerve and DRG, inhibited IL-4, IL-10, and IL-17A in the nerve, decreased β-endorphin, and enhanced substance P in the plasma, compared to the control. Responsive animals showed decreased NGF and increased IL-6 in the nerve, accompanied by restoration of local IL-10 and IL-17A and systemic β-endorphin. Refractory animals showed increased TNF-α and decreased IFNγ in the nerve, along with decreased TNF-α and IL-17A in the DRG, maintaining low levels of systemic β-endorphin. Our findings suggest that the effectiveness of MCS depends on local control of inflammatory and neurotrophic changes, accompanied by recovery of the opioidergic system observed in neuropathic conditions. So, understanding the refractoriness to MCS may guide an improvement in the efficacy of the technique, thus benefiting patients with persistent neuropathic pain.

Breast cancer is the second most common diagnosed type of cancer in women. Chronic neuropathic pain after mastectomy occurs frequently and is a serious health problem. In our previous single-center, prospective, randomized controlled clinical study, we demonstrated that the combination of serratus anterior plane block (SAM) and pectoral nerve block type I (PECS I) with general anesthesia reduced acute postoperative pain. The present report describes a prospective follow-up study of this published study to investigate the development of chronic neuropathic pain 12 months after mastectomy by comparing the use of general anesthesia alone and general anesthesia with SAM + PECS I. Additionally, the use of analgesic medication, quality of life, depressive symptoms, and possible correlations between plasma levels of interleukin (IL)-1 beta, IL-6, and IL-10 collected before and 24 h after surgery as predictors of pain and depression were evaluated. The results showed that the use of SAM + PECS I with general anesthesia reduced numbness, hypoesthesia to touch, the incidence of patients with chronic pain in other body regions and depressive symptoms, however, did not significantly reduce the incidence of chronic neuropathic pain after mastectomy. Additionally, there was no difference in the consumption of analgesic medication and quality of life. Furthermore, no correlation was observed between IL-1 beta, IL-6, and IL-10 levels and pain and depression. The combination of general anesthesia with SAM + PECS I reduced the occurrence of specific neuropathic pain descriptors and depressive symptoms. These results could promote the use of SAM + PECS I blocks for the prevention of specific neuropathic pain symptoms after mastectomy.Registration of clinical trial: The Research Ethics Board of the Hospital Sirio-Libanes/Brazil approved the study (CAAE 48721715.0.0000.5461). This study is registered at Registro Brasileiro de Ensaios Clinicos (ReBEC), and ClinicalTrials.gov, Identifier: NCT02647385., (© 2023. The Author(s).)

Background: Parkinson's disease (PD) is characterized by a progressive loss of nigrostriatal dopaminergic neurons with impaired motor and non-motor symptoms. It has been suggested that motor asymmetry could be caused due to an imbalance in dopamine levels, as visualized by dopamine transporter single emission computed tomography test (DAT-SPECT), which might be related to indirect measures of neurodegeneration, evaluated by the Montreal Cognitive Assessment (MOCA) and α-synuclein levels in the cerebrospinal fluid (CSF). Therefore, this study aimed to understand the correlation between disease laterality, DAT-SPECT, cognition, and α-synuclein levels in PD., Methods: A total of 28 patients in the moderate-advanced stage of PD were subjected to neurological evaluation, TRODAT-1-SPECT/CT imaging, MOCA, and quantification of the levels of α-synuclein., Results: We found that α-synuclein in the CSF was correlated with global cognition (positive correlation, r 2 = 0.3, p = 0.05) and DAT-SPECT concentration in the putamen (positive correlation, r 2 = 0.4, p = 0.005), and striatum (positive correlation, r 2 = 0.2, p = 0.03), thus working as a neurodegenerative biomarker. No other correlations were found between DAT-SPECT, CSF α-synuclein, and cognition, thus suggesting that they may be lost with disease progression., Conclusions: Our data highlight the importance of understanding the dysfunction of the dopaminergic system in the basal ganglia and its complex interactions in modulating cognition.

The use of deep brain stimulation (DBS) for the treatment of chronic pain was one of the first applications of this technique in functional neurosurgery. Established brain targets in the clinic include the periaqueductal (PAG)/periventricular gray matter (PVG) and sensory thalamic nuclei. More recently, the anterior cingulum (ACC) and the ventral striatum/anterior limb of the internal capsule (VS/ALIC) have been investigated for the treatment of emotional components of pain. In the clinic, most studies showed a response in 20%-70% of patients. In various applications of DBS, animal models either provided the rationale for the development of clinical trials or were utilized as a tool to study potential mechanisms of stimulation responses. Despite the complex nature of pain and the fact that animal models cannot reliably reflect the subjective nature of this condition, multiple preparations have emerged over the years. Overall, DBS was shown to produce an antinociceptive effect in rodents when delivered to targets known to induce analgesic effects in humans, suggesting a good predictive validity. Compared to the relatively high number of clinical trials in the field, however, the number of animal studies has been somewhat limited. Additional investigation using modern neuroscience techniques could unravel the mechanisms and neurocircuitry involved in the analgesic effects of DBS and help to optimize this therapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Pagano, Dale, Campos and Hamani.)

Glioblastoma (GBM) is a life-threatening disease that presents high morbidity and mortality. The standardized treatment protocol results in a global survival of less than three years in the majority of cases. Immunotherapies have gained wide recognition in cancer treatment; however, GBM has an immunosuppressive microenvironment diminishing the possible effectiveness of this therapy. In this sense, investigating the inflammatory settings and the tumoral nature of GBM patients are an important goal to create an individual plan of treatment to improve overall survival rate and quality of life of these patients. Thirty-two patients who underwent surgical resection of GBM were included in this study. Tumor samples and 10 mL of peripheral blood were collected and immediately frozen. TNF-a, IL-1a and IL-4 were evaluated in the tumor and TNF-a, IL-1a and TGF-b in the plasma by Luminex assay. Immunohistochemistry analysis to determine immune celular profile was done, including immunohistochemistry for CD20, CD68 and CD3. Three cases were excluded. Tumor topography, tumor nature, and tumor volume reconstructions were accurately analyzed by T1-weighted, T2-weighted, and FLAIR magnetic resonance imaging. We found that GBM patients with below median peripheral levels of TNF-a and IL-1a had a decreased survival rate when compared to above median patients. On the other hand, patients with below median peripheral levels of TGF-b increased overall survival rate. Intratumoral IL-1a above median was associated with higher number of macrophages and fewer with B cells. Furthermore, plasmatic TNF-a levels were correlated with intratumoral TNF-a levels, suggesting that peripheral cytokines are related to the tumoral microenvironment. Even though tumor size has no difference regarding survival rate, we found a negative correlation between intratumoral IL-4 and tumor size, where larger tumors have less IL-4 expression. Nevertheless, the tumoral nature had a significant effect in overall survival rate, considering that infiltrative tumors showed decreased survival rate and intratumoral TNF-a. Moreover, expansive tumors revealed fewer macrophages and higher T cells. In multiple variation analyzes, we demonstrated that infiltrative tumors and below median peripheral IL-1a expression represent 3 times and 5 times hazard ratio, respectively, demonstrating a poor prognosis. Here we found that peripheral cytokines had a critical role as prognostic tools in a small cohort of GBM patients., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is considered the gold-standard treatment for PD; however, underlying therapeutic mechanisms need to be comprehensively elucidated, especially in relation to glial cells. We aimed to understand the effects of STN-microlesions and STN-DBS on striatal glial cells, inflammation, and extracellular glutamate/GABAergic concentration in a 6-hydroxydopamine (6-OHDA)-induced PD rat model. Rats with unilateral striatal 6-OHDA and electrodes implanted in the STN were divided into two groups: DBS OFF and DBS ON (5 days/2 h/day). Saline and 6-OHDA animals were used as control. Akinesia, striatal reactivity for astrocytes, microglia, and inflammasome, and expression of cytokines, cell signaling, and excitatory amino acid transporter (EAAT)-2 were examined. Moreover, striatal microdialysis was performed to evaluate glutamate and GABA concentrations. The PD rat model exhibited akinesia, increased inflammation, glutamate release, and decreased glutamatergic clearance in the striatum. STN-DBS (DBS ON) completely abolished akinesia. Both STN-microlesion and STN-DBS decreased striatal cytokine expression and the relative concentration of extracellular glutamate. However, STN-DBS inhibited morphological changes in astrocytes, decreased inflammasome reactivity, and increased EAAT2 expression in the striatum. Collectively, these findings suggest that the beneficial effects of DBS are mediated by a combination of stimulation and local microlesions, both involving the inhibition of glial cell activation, neuroinflammation, and glutamate excitotoxicity., Competing Interests: The authors declare that they have no competing interests.

Pain and depression are complex disorders that frequently co-occur, resulting in diminished quality of life. The habenula is an epithalamic structure considered to play a pivotal role in the neurocircuitry of both pain and depression. The habenula can be divided into two major areas, the lateral and medial habenula, that can be further subdivided, resulting in 6 main subregions. Here, we investigated habenula activation patterns in a rat model of neuropathic pain with accompanying depressive-like behaviour. Wistar rats received active surgery for the development of neuropathic pain (chronic constriction injury of the sciatic nerve; CCI), sham surgery (surgical control), or no surgery (behavioural control). All animals were evaluated for mechanical nociceptive threshold using the paw pressure test and depressive-like behaviour using the forced swimming test, followed by evaluation of the immunoreactivity to cFos-a marker of neuronal activity-in the habenula and subregions. The Open Field Test was used to evaluate locomotor activity. Animals with peripheral neuropathy (CCI) showed decreased mechanical nociceptive threshold and increased depressive-like behaviour compared to control groups. The CCI group presented decreased cFos immunoreactivity in the total habenula, total lateral habenula and lateral habenula subregions, compared to controls. No difference was found in cFos immunoreactivity in the total medial habenula, however when evaluating the subregions of the medial habenula, we observed distinct activation patterns, with increase cFos immunoreactivity in the superior subregion and decrease in the central subregion. Taken together, our data suggest an involvement of the habenula in neuropathic pain and accompanying depressive-like behaviour., Competing Interests: The authors declare no commercial or financial relationships that could be construed as potential conflicts of interest.

Background: Neuropathic pain (NP) is a complex disease that remains challenging to treat. Low-frequency dense-and-disperse (DD) electroacupuncture (EA) has been used as adjuvant therapy for neuropathic pain; however, its analgesic effect decreases as stimulation time increases, or when it is repeatedly used. We hypothesized that a new frequency parameter could improve the effectiveness of EA, and aimed to compare the efficacy and duration of the analgesic effect between classic DD-EA and non-repetitive and non-sequential frequency (random frequency (RF)-EA) in neuropathic rats. Furthermore, the effect of RF-EA at local traditional acupuncture point locations versus auricular vagus nerve stimulation (aVNS) was evaluated., Methods: Male Wistar rats with peripheral neuropathy were subjected to a single session of DD-EA or RF-EA for 20 or 40 min at ST36 + GB34. An additional group of rats was treated with RF-EA for 20 min using aVNS at the appropriate ear point locations. Paw pressure test, von Frey filaments and spontaneous pain scores were evaluated. Sham-operated rats were used as controls., Results: In all, 20 min of RF-EA reversed hyperalgesia (for 24 h) and allodynia (for 8 h), showing a longer analgesic effect than DD-EA. Both RF-EA and DD-EA induced partial inhibition of spontaneous pain for 8 h. Forty minutes of DD-EA did not interfere with the NP phenomena; however, RF-EA induced significant long-term analgesia. aVNS induced an analgesic effect similar to local stimulation., Conclusion: This pilot study shows that RF-EA at both local traditional acupuncture point and auriculotherapy point locations induces long-lasting analgesia in neuropathic rats, and more effectively so than classical DD-EA.

Multiple sclerosis (MS) is a demyelinating disease of inflammatory and autoimmune origin, which induces sensory and progressive motor impairments, including pain. Cells of the immune system actively participate in the pathogenesis and progression of MS by inducing neuroinflammation, tissue damage, and demyelination. Crotalphine (CRO), a structural analogue to a peptide firstly identified in Crotalus durissus terrificus snake venom, induces analgesia by endogenous opioid release and type 2 cannabinoid receptor (CB2) activation. Since CB2 activation downregulates neuroinflammation and ameliorates symptoms in mice models of MS, it was presently investigated whether CRO has a beneficial effect in the experimental autoimmune encephalomyelitis (EAE). CRO was administered on the 5th day after immunization, in a single dose, or five doses starting at the peak of disease. CRO partially reverted EAE-induced mechanical hyperalgesia and decreased the severity of the clinical signs. In addition, CRO decreases the inflammatory infiltrate and glial cells activation followed by TNF-α and IL-17 downregulation in the spinal cord. Peripherally, CRO recovers the EAE-induced impairment in myelin thickness in the sciatic nerve. Therefore, CRO interferes with central and peripheral neuroinflammation, opening perspectives to MS control.

Persistent pain is a prevalent symptom of Parkinson's disease (PD), which is related to the loss of monoamines and neuroinflammation. Motor cortex stimulation (MCS) inhibits persistent pain by activating the descending analgesic pathways; however, its effectiveness in the control of PD-induced pain remains unclear. Here, we evaluated the analgesic efficacy of MCS together with serotonergic and spinal glial modulation in an experimental PD (ePD) rat model. Wistar rats with unilateral striatal 6-OHDA and MCS were assessed for behavioral immobility and nociceptive responses. The immunoreactivity of dopamine in the substantia nigra and serotonin in the nucleus raphe magnus (NRM) and the neuronal, astrocytic, and microglial activation in the dorsal horn of the spinal cord were evaluated. MCS, without interfering with dopamine loss, reversed ePD-induced immobility and hypernociception. This response was accompanied by an exacerbated increase in serotonin in the NRM and a decrease in neuronal and astrocytic hyperactivation in the spinal cord, without inhibiting ePD-induced microglial hypertrophy and hyperplasia. Taken together, MCS induces analgesia in the ePD model, while restores the descending serotonergic pathway with consequent inhibition of spinal neurons and astrocytes, showing the role of MCS in PD-induced pain control.

Stroke is a multiphasic process involving a direct ischemic brain injury which is then exacerbated by the influx of immune cells into the brain tissue. Activation of brain endothelial cells leads to the expression of adhesion molecules such vascular cell adhesion molecule 1 (VCAM-1) on endothelial cells, further increasing leukocyte recruitment. Polymerase δ-interacting protein 2 (Poldip2) promotes brain vascular inflammation and leukocyte recruitment via unknown mechanisms. This study aimed to define the role of Poldip2 in mediating vascular inflammation and leukocyte recruitment following cerebral ischemia. Cerebral ischemia was induced in Poldip2 +/+ and Poldip2 +/- mice and brains were isolated and processed for flow cytometry or RT-PCR. Cultured rat brain microvascular endothelial cells were used to investigate the effect of Poldip2 depletion on focal adhesion kinase (FAK)-mediated VCAM-1 induction. Poldip2 depletion in vivo attenuated the infiltration of myeloid cells, inflammatory monocytes/macrophages and decreased the induction of adhesion molecules. Focusing on VCAM-1, we demonstrated mechanistically that FAK activation was a critical intermediary in Poldip2-mediated VCAM-1 induction. In conclusion, Poldip2 is an important mediator of endothelial dysfunction and leukocyte recruitment. Thus, Poldip2 could be a therapeutic target to improve morbidity following ischemic stroke.

Background: Novel coronavirus disease (COVID-19) morbidity is not restricted to the respiratory system, but also affects the nervous system. Non-invasive neuromodulation may be useful in the treatment of the disorders associated with COVID-19. Objective: To describe the rationale and empirical basis of the use of non-invasive neuromodulation in the management of patients with COVID-10 and related disorders. Methods: We summarize COVID-19 pathophysiology with emphasis of direct neuroinvasiveness, neuroimmune response and inflammation, autonomic balance and neurological, musculoskeletal and neuropsychiatric sequela. This supports the development of a framework for advancing applications of non-invasive neuromodulation in the management COVID-19 and related disorders. Results: Non-invasive neuromodulation may manage disorders associated with COVID-19 through four pathways: (1) Direct infection mitigation through the stimulation of regions involved in the regulation of systemic anti-inflammatory responses and/or autonomic responses and prevention of neuroinflammation and recovery of respiration; (2) Amelioration of COVID-19 symptoms of musculoskeletal pain and systemic fatigue; (3) Augmenting cognitive and physical rehabilitation following critical illness; and (4) Treating outbreak-related mental distress including neurological and psychiatric disorders exacerbated by surrounding psychosocial stressors related to COVID-19. The selection of the appropriate techniques will depend on the identified target treatment pathway. Conclusion: COVID-19 infection results in a myriad of acute and chronic symptoms, both directly associated with respiratory distress (e.g., rehabilitation) or of yet-to-be-determined etiology (e.g., fatigue). Non-invasive neuromodulation is a toolbox of techniques that based on targeted pathways and empirical evidence (largely in non-COVID-19 patients) can be investigated in the management of patients with COVID-19., (Copyright © 2020 Baptista, Baltar, Okano, Moreira, Campos, Fernandes, Brunoni, Badran, Tanaka, de Andrade, da Silva Machado, Morya, Trujillo, Swami, Camprodon, Monte-Silva, Sá, Nunes, Goulardins, Bikson, Sudbrack-Oliveira, de Carvalho, Duarte-Moreira, Pagano, Shinjo and Zana.)

Because environmental elements modify chronic pain development and endogenous mechanisms of pain control are still a great therapeutic source, we investigated the effects of an early exposure to environmental enrichment (EE) in a translational model of neuropathic pain. Young male rats born and bred in an enriched environment, which did not count on running wheel, underwent chronic constriction injury (CCI) of sciatic nerve. EE abolished neuropathic pain behavior 14 days after CCI. Opioid receptors' antagonism reversed EE-analgesic effect. β-endorphin and met-enkephalin serum levels were increased only in EE-CCI group. Blockade of glucocorticoid receptors did not alter EE-analgesic effect, although corticosterone circulating levels were increased in EE animals. In the spinal cord, EE controlled CCI-induced serotonin increase. In DRG, EE blunted the expression of ATF-3 after CCI. Surprisingly, EE-CCI group showed a remarkable preservation of sciatic nerve fibers compared to NE-CCI group. This work demonstrated global effects induced by an EE protocol that explain, in part, the protective role of EE upon chronic noxious stimulation, reinforcing the importance of endogenous mechanisms in the prevention of chronic pain development., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest to declare., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective therapeutic strategy for motor symptoms of Parkinson's disease (PD) when L-DOPA therapy induces disabling side effects. Classical inflammatory activation of glial cells is well established in PD, contributing to the progressive neurodegenerative state; however, the role of DBS in regulating the inflammatory response remains largely unknown. To understand the involvement of astrocytes in the mechanisms of action of DBS, we evaluated the effect of STN-DBS in regulating motor symptoms, astrocyte reactivity, and cytokine expression in a 6-OHDA-induced PD rat model. To mimic in vivo DBS, we investigate the effect of high-frequency stimulation (HFS) in cultured astrocytes regulating cytokine induction and NF-κB activation. We found that STN-DBS improved motor impairment, induced astrocytic hyperplasia, and reversed increased IFN-γ and IL-10 levels in the globus pallidus (GP) of lesioned rats. Moreover, HFS activated astrocytes and prevented TNF-α-induced increase of monocyte chemoattractant protein-1 (MCP-1) and NF-κB activation in vitro. Our results indicate that DBS/HFS may act as a regulator of the inflammatory response in PD states, attenuating classical activation of astrocytes and cytokine induction, potentially through its ability to regulate NF-κB activation. These findings may help us understand the role of astrocyte signaling in HFS, highlighting its possible relationship with the effectiveness of DBS in neurodegenerative disorders.

Chronic pain is a serious public health problem with a strong affective-motivational component that makes it difficult to treat. Most patients with chronic pain suffer from severe depression; hence, both conditions coexist and exacerbate one another. Brain inflammatory mediators are critical for maintaining depression-pain syndrome and could be substrates for it. The goal of our paper was to review clinical and preclinical findings to identify the neuroinflammatory profile associated with the cooccurrence of pain and depression. In addition, we aimed to explore the regulatory effect of neuronal reorganization on the inflammatory response in pain and depression. We conducted a quantitative review supplemented by manual screening. Our results revealed inflammatory signatures in different preclinical models and clinical articles regarding depression-pain syndrome. We also identified that improvements in depressive symptoms and amelioration of pain can be modulated through direct targeting of inflammatory mediators, such as cytokines and molecular inhibitors of the inflammatory cascade. Additionally, therapeutic targets that improve and regulate the synaptic environment and its neurotransmitters may act as anti-inflammatory compounds, reducing local damage-associated molecular patterns and inhibiting the activation of immune and glial cells. Taken together, our data will help to better elucidate the neuroinflammatory profile in pain and depression and may help to identify pharmacological targets for effective management of depression-pain syndrome., (Copyright © 2020 Campos, Antunes, Matsumoto, Pagano and Martinez.)

Objective: Motor cortex stimulation (MCS) is a neurosurgical technique used to treat patients with refractory neuropathic pain syndromes. MCS activates the periaqueductal gray (PAG) matter, which is one of the major centers of the descending pain inhibitory system. However, the neurochemical mechanisms in the PAG that underlie the analgesic effect of MCS have not yet been described. The main goal of this study was to investigate the neurochemical mechanisms involved in the analgesic effect induced by MCS in neuropathic pain. Specifically, we investigated the release of γ-aminobutyric acid (GABA), glycine, and glutamate in the PAG and performed pharmacological antagonism experiments to validate of our findings., Methods: Male Wistar rats with surgically induced chronic constriction of the sciatic nerve, along with sham-operated rats and naive rats, were implanted with both unilateral transdural electrodes in the motor cortex and a microdialysis guide cannula in the PAG and subjected to MCS. The MCS was delivered in single 15-minute sessions. Neurotransmitter release was evaluated in the PAG before, during, and after MCS. Quantification of the neurotransmitters GABA, glycine, and glutamate was performed using a high-performance liquid chromatography system. The mechanical nociceptive threshold was evaluated initially, on the 14th day following the surgery, and during the MCS. In another group of neuropathic rats, once the analgesic effect after MCS was confirmed by the mechanical nociceptive test, rats were microinjected with saline or a glycine antagonist (strychnine), a GABA antagonist (bicuculline), or a combination of glycine and GABA antagonists (strychnine+bicuculline) and reevaluated for the mechanical nociceptive threshold during MCS., Results: MCS reversed the hyperalgesia induced by peripheral neuropathy in the rats with chronic sciatic nerve constriction and induced a significant increase in the glycine and GABA levels in the PAG in comparison with the naive and sham-treated rats. The glutamate levels remained stable under all conditions. The antagonism of glycine, GABA, and the combination of glycine and GABA reversed the MCS-induced analgesia., Conclusions: These results suggest that the neurotransmitters glycine and GABA released in the PAG may be involved in the analgesia induced by cortical stimulation in animals with neuropathic pain. Further investigation of the mechanisms involved in MCS-induced analgesia may contribute to clinical improvements for the treatment of persistent neuropathic pain syndromes.

Background: Sepsis-associated encephalopathy (SAE), a diffuse cerebral dysfunction in the absence of direct CNS infection, is associated with increased rates of mortality and morbidity in patients with sepsis. Increased cytokine production and disruption of the blood-brain barrier (BBB) are implicated in the pathogenesis of SAE. The induction of pro-inflammatory mediators is driven, in part, by activation of NF-κΒ. Lipopolysaccharide (LPS), an endotoxin produced by gram-negative bacteria, potently activates NF-κΒ and its downstream targets, including cyclooxygenase-2 (Cox-2). Cox-2 catalyzes prostaglandin synthesis and in the brain prostaglandin, E2 is capable of inducing endothelial permeability. Depletion of polymerase δ-interacting protein 2 (Poldip2) has previously been reported to attenuate BBB disruption, possibly via regulation of NF-κΒ, in response to ischemic stroke. Here we investigated Poldip2 as a novel regulator of NF-κΒ/cyclooxygenase-2 signaling in an LPS model of SAE., Methods: Intraperitoneal injections of LPS (18 mg/kg) were used to induce BBB disruption in Poldip2 +/+ and Poldip2 +/- mice. Changes in cerebral vascular permeability and the effect of meloxicam, a selective Cox-2 inhibitor, were assessed by Evans blue dye extravasation. Cerebral cortices of Poldip2 +/+ and Poldip2 +/- mice were further evaluated by immunoblotting and ELISA. To investigate the role of endothelial Poldip2, immunofluorescence microscopy and immunoblotting were performed to study the effect of siPoldip2 on LPS-mediated NF-κΒ subunit p65 translocation and Cox-2 induction in rat brain microvascular endothelial cells. Finally, FITC-dextran transwell assay was used to assess the effect of siPoldip2 on LPS-induced endothelial permeability., Results: Heterozygous deletion of Poldip2 conferred protection against LPS-induced BBB permeability. Alterations in Poldip2 +/+ BBB integrity were preceded by induction of Poldip2, p65, and Cox-2, which was not observed in Poldip2 +/- mice. Consistent with these findings, prostaglandin E2 levels were significantly elevated in Poldip2 +/+ cerebral cortices compared to Poldip2 +/- cortices. Treatment with meloxicam attenuated LPS-induced BBB permeability in Poldip2 +/+ mice, while having no significant effect in Poldip2 +/- mice. Moreover, silencing of Poldip2 in vitro blocked LPS-induced p65 nuclear translocation, Cox-2 expression, and endothelial permeability., Conclusions: These data suggest Poldip2 mediates LPS-induced BBB disruption by regulating NF-κΒ subunit p65 activation and Cox-2 and prostaglandin E2 induction. Consequently, targeted inhibition of Poldip2 may provide clinical benefit in the prevention of sepsis-induced BBB disruption.

Pain is a common nonmotor symptom of Parkinson's disease (PD) that remains neglected and misunderstood. Elucidating the nondopaminergic circuitry may be key to better understanding PD and improving current treatments. We investigated the role of monoamines in nociceptive behavior and descending analgesic circuitry in a rat 6-hydroxydopamine (6-OHDA)-induced PD model and explored the resulting motor dysfunctions and inflammatory responses. Rats pretreated with noradrenaline and serotonin reuptake inhibitors were given unilateral striatal 6-OHDA injections and evaluated for mechanical hyperalgesia and motor impairments. Through immunohistochemistry, the number and activation of neurons, and the staining for astrocytes, microglia and enkephalin were evaluated in specific brain structures and the dorsal horn of the spinal cord. The PD model induced bilateral mechanical hyperalgesia that was prevented by reuptake inhibitors in the paw contralateral to the lesion. Reuptake inhibitors also prevented postural immobility and asymmetric rotational behavior in PD rats without interfering with dopaminergic neuron loss or glial activation in the substantia nigra. However, the inhibitors changed the periaqueductal gray circuitry, protected against neuronal impairment in the locus coeruleus and nucleus raphe magnus, and normalized spinal enkephalin and glial staining in lesioned rats. These data indicate that the preservation of noradrenergic and serotonergic systems regulates motor responses and nociceptive circuitry during PD not by interfering directly with nigral lesions but by modulating the opioid system and glial response in the spinal cord. Taken together, these results suggest that nondopaminergic circuitry is essential to the motor and nonmotor symptoms of PD and must be further investigated., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Parkinson's disease (PD) is a neurodegenerative disorder that causes progressive dysfunction of dopaminergic and non-dopaminergic neurons, generating motor and nonmotor signs and symptoms. Pain is reported as the most bothersome nonmotor symptom in PD; however, pain remains overlooked and poorly understood. In this study, we evaluated the nociceptive behavior and the descending analgesia circuitry in a rat model of PD. Three independent experiments were performed to investigate: i) thermal nociceptive behavior; ii) mechanical nociceptive behavior and dopaminergic repositioning; and iii) modulation of the pain control circuitry. The rat model of PD, induced by unilateral striatal 6-hydroxydopamine (6-OHDA), did not interfere with thermal nociceptive responses; however, the mechanical nociceptive threshold was decreased bilaterally compared to that of naive or striatal saline-injected rats. This response was reversed by apomorphine or levodopa treatment. Striatal 6-OHDA induced motor impairments and reduced dopaminergic neuron immunolabeling as well as the pattern of neuronal activation (c-Fos) in the substantia nigra ipsilateral (IPL) to the lesion. In the midbrain periaqueductal gray (PAG), 6-OHDA-induced lesion increased IPL and decreased contralateral PAG GABAergic labeling compared to control. In the dorsal horn of the spinal cord, lesioned rats showed bilateral inhibition of enkephalin and μ-opioid receptor labeling. Taken together, we demonstrated that the unilateral 6-OHDA-induced PD model induces bilateral mechanical hypernociception, which is reversed by dopamine restoration, changes in the PAG circuitry, and inhibition of spinal opioidergic regulation, probably due to impaired descending analgesic control. A better understanding of pain mechanisms in PD patients is critical for developing better therapeutic strategies to improve their quality of life., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Multiple sclerosis (MS) is an inflammatory disease of the CNS, characterized by demyelination, focal inflammatory infiltrates and axonal damage. Oxidative stress has been linked to MS pathology. Previous studies have suggested the involvement of NADPH oxidase 2 (Nox2), an enzyme that catalyzes the reduction of oxygen to produce reactive oxygen species, in the MS pathogenesis. The mechanisms of Nox2 activation on MS are unknown. The purpose of this study was to investigate the effect of Nox2 deletion on experimental autoimmune encephalomyelitis (EAE) onset and severity, on astrocyte activation as well as on pro-inflammatory and anti-inflammatory cytokine induction in striatum and motor cortex., Methodology: Subcutaneous injection of MOG35-55 emulsified with complete Freund's adjuvant was used to evaluate the effect of Nox2 depletion on EAE-induced encephalopathy. Striatum and motor cortices were isolated and evaluated by immunoblotting and RT-PCR., Results: Nox2 deletion resulted in clinical improvement of the disease and prevented astrocyte activation following EAE induction. Nox2 deletion prevented EAE-induced induction of pro-inflammatory cytokines and stimulated the expression of the anti-inflammatory cytokines IL-4 and IL-10., Conclusions: Our data suggest that Nox2 is involved on the EAE pathogenesis. IL-4 and IL-10 are likely to be involved on the protective mechanism observed following Nox2 deletion., Competing Interests: Conflict of interest The author has no conflicts of interest related to this work.

Motor cortex stimulation (MCS) is an effective therapy for refractory neuropathic pain. MCS increases the nociceptive threshold in healthy rats via endogenous opioids, inhibiting thalamic nuclei and activating the periaqueductal gray. It remains unclear how the motor cortex induces top-down modulation of pain in the absence of persistent pain. Here, we investigated the main nuclei involved in the descending analgesic pathways and the spinal nociceptive neurons in rats that underwent one session of MCS and were evaluated with the paw pressure nociceptive test. The pattern of neuronal activation in the dorsal raphe nucleus (DRN), nucleus raphe magnus (NRM), locus coeruleus (LC), and dorsal horn of the spinal cord (DHSC) was assessed by immunoreactivity (IR) for Egr-1 (a marker of activated neuronal nuclei). IR for serotonin (5HT) in the DRN and NRM, tyrosine hydroxylase (TH) in the LC, and substance P (SP) and enkephalin (ENK) in the DHSC was also evaluated. MCS increased the nociceptive threshold of the animals; this increase was accompanied by activation of the NRM, while DRN activation was unchanged. However, cortical stimulation induced an increase in 5HT-IR in both serotonergic nuclei. MCS did not change the activation pattern or TH-IR in the LC, and it inhibited neuronal activation in the DHSC without altering SP or ENK-IR. Taken together, our results suggest that MCS induces the activation of serotonergic nuclei as well as the inhibition of spinal neurons, and such effects may contribute to the elevation of the nociceptive threshold in healthy rats. These results allow a better understanding of the circuitry involved in the antinociceptive top-down effect induced by MCS under basal conditions, reinforcing the role of primary motor cortex in pain control.

The amygdala is an important component of the limbic system that participates in the control of the pain response and modulates the affective-motivational aspect of pain. Neuropathic pain is a serious public health problem and has a strong affective-motivational component that makes it difficult to treat. The central (CeA), basolateral (BLA) and lateral (LA) nuclei of the amygdala are involved in the processing and regulation of chronic pain. However, the roles of these nuclei in the maintenance of neuropathic pain, anxiety and depression remain unclear. Thus, the main objective of this study was to investigate the role of amygdala subnuclei in the modulation of neuropathic pain, including the affective-motivational axis, in an experimental model of peripheral neuropathy. The specific goals were as follows: (1) To evaluate the nociceptive responses and the patterns of activation of the CeA, BLA and LA in neuropathic rats; and (2) To evaluate the effect of inactivating the amygdala nuclei on the nociceptive response, anxiety and depressive behaviors, motor activity, and plasma stress hormones in animals with neuropathic pain. Thus, mechanical hyperalgesia and allodynia, and the pattern of c-Fos staining in the amygdala subnuclei were evaluated in rats with chronic constriction of the sciatic nerve, as well as sham-operated and naïve rats. Once the amygdala subnuclei involved in neuropathic pain response were defined, those subnuclei were pharmacological inactivated. The effect of muscimol inactivation on the nociceptive response (hyperalgesia and allodynia), anxiety (elevated plus-maze), depressive-like behavior (forced swim test), motor activity (open field), and plasma stress hormone levels (corticosterone and adrenocorticotropic hormone) were evaluated in sham-operated and neuropathic animals. The results showed that the anterior and posterior portions of the BLA and the central portion of the CeA are involved in controlling neuropathic pain. The inactivation of these nuclei reversed hyperalgesia, allodynia and depressive-like behavior in animals with peripheral neuropathy. Taken together, our findings improve our understanding of the neurocircuitry involved in persistent pain and the roles of specific amygdala subnuclei in the modulation of neuropathic pain, including the neurocircuitry that processes the affective-motivational component of pain.

Ameloblastoma is a locally aggressive neoplasm with a poorly understood pathogenesis. Therefore, the aim of this study is to investigate whether COX-2 expression is associated with ameloblastoma microvascular density (MVD) and with tumor aggressiveness. Sixty-three cases of primary ameloblastomas arranged in tissue microarray were submitted to immunohistochemistry against cyclooxigenase-2 (COX-2) and CD34. Clinicopathological parameters regarding sex, age, tumour size, tumour duration, tumour location, treatment, recurrences, radiographic features, vestibular/lingual and basal cortical disruption and follow-up data were obtained from patients' medical records and correlated with the proteins expression. The results on BRAF-V600E expression were obtained from our previous study and correlated with COX-2 and CD34 expressions. Log-rank univariate analysis and multivariate Cox regression model were done to investigate the prognostic potential of the molecular markers. Twenty-eight cases (44.4%) exhibited cytoplasmic positivity for COX-2, predominantly in the columnar peripheral cells, with a mean MVD of 2.2 vessels/mm 2 . COX-2 was significantly associated with recurrences (p < 0.001) and BRAF-V600E expression (p < 0.001), whereas lower MVD was associated with the use of conservative therapy (p = 0.004). Using univariate and multivariate analyses, COX-2 was significantly associated with a lower 5-year disease-free survival (DFS) rate (p < 0.001 and p = 0.012, respectively), but not with a higher MVD (p = 0.68). In conclusion, COX-2 expression in ameloblastomas is not associated with MVD, but it is significantly associated with recurrences and with a lower DFS., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Surgery is the first-line treatment for early, localized, or operable breast cancer. Regional anesthesia during mastectomy may offer the prevention of postoperative pain. One potential protocol is the combination of serratus anterior plane block (SAM block) with pectoral nerve block I (PECS I), but the results and potential benefits are limited. Our study compared general anesthesia with or without SAM block + PECS I during radical mastectomy with axillary node dissection and breast reconstruction using evaluations of pain, opioid consumption, side effects and serum levels of interleukin (IL)-1beta, IL-6 and IL-10. This is a prospective, randomized controlled trial. Fifty patients were randomized to general anesthesia only or general anesthesia associated with SAM block + PECS I (25 per group). The association of SAM block + PECS I with general anesthesia reduced intraoperative fentanyl consumption, morphine use and visual analog pain scale scores in the post-anesthetic care unit (PACU) and at 24 h after surgery. In addition, the anesthetic protocol decreased side effects and sedation 24 h after surgery compared to patients who underwent general anesthesia only. IL-6 levels increased after the surgery compared to baseline levels in both groups, and no differences in IL-10 and IL-1 beta levels were observed. Our protocol improved the outcomes of mastectomy, which highlight the importance of improving mastectomy protocols and focusing on the benefits of regional anesthesia.

Lessons Learned: Pregabalin is a medication that can decrease neuronal hyperexcitability, relieve neuropathic pain, and reach stable plasma levels after a titration period of only a few days.Its use during oxaliplatin infusions was not able to decrease the incidence of chronic, oxalipaltin-related neuropathic pain, compared with placebo., Background: Patients with colorectal cancer (CRC) receiving oxaliplatin (OXA) develop acute and chronic painful oxaliplatin-induced peripheral neuropathy (OXAIPN). Acute and chronic OXA-related neuropathies have different pathophysiological bases, but both lead to a common phenomenon: central sensitization (CS) of nociceptive neuronal networks, leading to increased sensitivity (hyperlgesia, allodynia) in the somatosensory system, the common ground of chronic neuropathic pain. Because CS is related to increased risk of painful OXAIPN, we hypothesized that preemptive use of the anti-hyperalgesic drug pregabaline (known to decrease CS) during OXA infusions would decrease the incidence of chronic OXAIPN., Methods: Pain-free, chemotherapy-naïve CRC patients receiving at least one cycle of modified-FLOX [5-FU(500 mg/m 2 )+leucovorin(20 mg/m 2 )/week for] 6 weeks+oxaliplatin(85 mg/m 2 ) at weeks 1-3-5 every 8 weeks] were randomized (1:1) into the study. Patients received either pregabalin or placebo for 3 days before and 3 days after each OXA infusion and were followed for up to 6 months. Clinical assessments were performed at baseline, at the end of chemotherapy, and after the follow-up period. The main outcome was average pain at the last visit assessed by the visual analogic scale (0-10) item of the Brief Pain Inventory (BPI). Secondary endpoints were presence of neuropathic pain according to the Douleur Neuropathique-4 (DN-4), pain dimensions (short- form McGill Pain Questionnaire [MPQ]), Neuropathic Pain Symptom Inventory (NPSI), and changes in nerve conduction studies (NCS) and side effect profile., Results: One hundred ninety-nine patients (57.0 ± 10.7 years old, 98 female, 101 male) were randomized. Data from 56 patients were not included in the analyses (as they did not receive at least one full cycle of modified FLOX). Data from 78 patients in the pregabalin group and 65 patients in the placebo group were retained for analyses. At the last visit, pain intensity in the pregabalin group was 1.03 (95% confidence interval [CI] = 0.79-1.26), and 0.85 (95% CI = 0.64-1.06) in the placebo group, which did not reach significance. Scores from the BPI, MPQ, DN-4, NPSI, and NCS and side-effect profiles and incidence of death did not differ between groups. Quality of life (QoL) score did not differ between groups (placebo = 76.9 ± 23.1, pregabalin group 79.4 ± 20.6). Mood scores were not significantly different between groups (placebo 9.7 [8.1-11.2]; pregabalin 6.8 [5.6-8.0])., Conclusion: The preemptive use of pregabalin during OXA infusions was safe, but did not decrease the incidence of chronic pain related to OXAIPN., (©AlphaMedPress; the data published online to support this summary is the property of the authors.)

Transcranial direct current stimulation (tDCS) is an emerging, noninvasive technique of neurostimulation for treating pain. However, the mechanisms and pathways involved in its analgesic effects are poorly understood. Therefore, we investigated the effects of direct current stimulation (DCS) on thermal and mechanical nociceptive thresholds and on the activation of the midbrain periaqueductal gray (PAG) and the dorsal horn of the spinal cord (DHSC) in rats; these central nervous system areas are associated with pain processing. Male Wistar rats underwent cathodal DCS of the motor cortex and, while still under stimulation, were evaluated using tail-flick and paw pressure nociceptive tests. Sham stimulation and naive rats were used as controls. We used a randomized design; the assays were not blinded to the experimenter. Immunoreactivity of the early growth response gene 1 (Egr-1), which is a marker of neuronal activation, was evaluated in the PAG and DHSC, and enkephalin immunoreactivity was evaluated in the DHSC. DCS did not change the thermal nociceptive threshold; however, it increased the mechanical nociceptive threshold of both hind paws compared with that of controls, characterizing a topographical effect. DCS decreased the Egr-1 labeling in the PAG and DHSC as well as the immunoreactivity of spinal enkephalin. Altogether, the data suggest that DCS disinhibits the midbrain descending analgesic pathway, consequently inhibiting spinal nociceptive neurons and causing an increase in the nociceptive threshold. This study reinforces the idea that the motor cortex participates in the neurocircuitry that is involved in analgesia and further clarifies the mechanisms of action of tDCS in pain treatment.

Gliomas are the most common type among all central nervous system tumors. The aggressiveness of gliomas is correlated with the level of angiogenesis and is often associated with prognosis. The aim of this study is to evaluate the novel GX1 peptide and the heterodimer RGD-GX1 radiolabeled with technetium-99m, for angiogenesis detection in glioma models. Radiolabeling and radiochemical controls were assessed for both radioconjugates. In vitro binding studies in glioma tumor cells were performed, as well as biodistribution in SCID mice bearing tumor cells, in order to evaluate the biological behavior and tumor uptake of the radiocomplexes. Blocking and imaging studies were also conducted. MicroSPECT/CT images were acquired in animals with experimentally implanted intracranial tumor. Open field activity was performed to evaluate behavior, as well as perfusion and histology analysis. The radiochemical purity of both radiotracers was greater than 96 %. In vitro binding studies revealed rather similar binding profi le for each molecule. The highest binding was for RGD-GX1 peptide at 120 min in U87MG cells (1.14 ± 0.35 %). Tumor uptake was also favorable for RGD-GX1 peptide in U87MG cells, reaching 2.96 ± 0.70 % at 1 h p.i. with 47 % of blocking. Imaging studies also indicated better visualization for RGD-GX1 peptide in U87MG cells. Behavior evaluation pointed brain damage and histology studies confirmed actual tumor in the uptake site. The results with the angiogenesis seeking molecule (99m)Tc-HYNIC-E-[c(RGDfk)-c(GX1)] were successful, and better than with (99m)Tc-HYNIC-PEG4-c(GX1). Future studies targeting angiogenesis in other glioma and nonglioma tumor models are recommended.

Background: Motor cortex stimulation (MCS) is an effective treatment in neuropathic pain refractory to pharmacological management. However, analgesia is not satisfactorily obtained in one third of patients. Given the importance of understanding the mechanisms to overcome therapeutic limitations, we addressed the question: what mechanisms can explain both MCS effectiveness and refractoriness? Considering the crucial role of spinal neuroimmune activation in neuropathic pain pathophysiology, we hypothesized that modulation of spinal astrocyte and microglia activity is one of the mechanisms of action of MCS., Methods: Rats with peripheral neuropathy (chronic nerve injury model) underwent MCS and were evaluated with a nociceptive test. Following the test, these animals were divided into two groups: MCS-responsive and MCS-refractory. We also evaluated a group of neuropathic rats not stimulated and a group of sham-operated rats. Some assays included rats with peripheral neuropathy that were treated with AM251 (a cannabinoid antagonist/inverse agonist) or saline before MCS. Finally, we performed immunohistochemical analyses of glial cells (microglia and astrocytes), cytokines (TNF-α and IL-1β), cannabinoid type 2 (CB2), μ-opioid (MOR), and purinergic P2X4 receptors in the dorsal horn of the spinal cord (DHSC)., Findings: MCS reversed mechanical hyperalgesia, inhibited astrocyte and microglial activity, decreased proinflammatory cytokine staining, enhanced CB2 staining, and downregulated P2X4 receptors in the DHSC ipsilateral to sciatic injury. Spinal MOR staining was also inhibited upon MCS. Pre-treatment with AM251 blocked the effects of MCS, including the inhibitory mechanism on cells. Finally, MCS-refractory animals showed similar CB2, but higher P2X4 and MOR staining intensity in the DHSC in comparison to MCS-responsive rats., Conclusions: These results indicate that MCS induces analgesia through a spinal anti-neuroinflammatory effect and the activation of the cannabinoid and opioid systems via descending inhibitory pathways. As a possible explanation for MCS refractoriness, we propose that CB2 activation is compromised, leading to cannabinoid resistance and consequently to the perpetuation of neuroinflammation and opioid inefficacy.

The protein S100A9 plays a key role in the control of inflammatory response. The C-terminus of the murine S100A9 protein (mS100A9p) downregulates the spreading and phagocytic activity of adherent peritoneal cells. Murine peritoneal cells are constituted by macrophages and B-1 cells, and the latter exert an inhibitory effect on macrophage functions by secreting interleukin- (IL-) 10. Here, we investigated the influence of B-1 cells on the inhibitory effect evoked by mS100A9p on macrophages. mS100A9p did not alter spreading and phagocytosis either by peritoneal macrophages obtained from mice deprived of B-1 cells or by bone marrow-derived macrophages (BMDMϕ). Nevertheless, when BMDMϕ were cocultivated by direct or indirect contact with B-1 cells treated with mS100A9p, the phagocytosis by BMDMϕ was decreased, showing that the effect of mS100A9p on macrophages was modulated by B-1 cells and/or their secretory compounds. Furthermore, the inhibitory action of mS100A9p on phagocytosis by adherent peritoneal cells was abolished in cells obtained from IL-10 knockout mice. Taken together, the results show that mS100A9p has no direct inhibitory effect on macrophages; however, mS100A9p modulates B-1 cells, which in turn downregulates macrophages, at least in part, via IL-10. These data contribute to the characterization of S100A9 functions involving B-1 cells in the regulation of the inflammatory process.

Motor cortex stimulation is generally suggested as a therapy for patients with chronic and refractory neuropathic pain. However, the mechanisms underlying its analgesic effects are still unknown. In a previous study, we demonstrated that cortical stimulation increases the nociceptive threshold of naive conscious rats with opioid participation. In the present study, we investigated the neurocircuitry involved during the antinociception induced by transdural stimulation of motor cortex in naive rats considering that little is known about the relation between motor cortex and analgesia. The neuronal activation patterns were evaluated in the thalamic nuclei and midbrain periaqueductal gray. Neuronal inactivation in response to motor cortex stimulation was detected in thalamic sites both in terms of immunolabeling (Zif268/Fos) and in the neuronal firing rates in ventral posterolateral nuclei and centromedian-parafascicular thalamic complex. This effect was particularly visible for neurons responsive to nociceptive peripheral stimulation. Furthermore, motor cortex stimulation enhanced neuronal firing rate and Fos immunoreactivity in the ipsilateral periaqueductal gray. We have also observed a decreased Zif268, δ-aminobutyric acid (GABA), and glutamic acid decarboxylase expression within the same region, suggesting an inhibition of GABAergic interneurons of the midbrain periaqueductal gray, consequently activating neurons responsible for the descending pain inhibitory control system. Taken together, the present findings suggest that inhibition of thalamic sensory neurons and disinhibition of the neurons in periaqueductal gray are at least in part responsible for the motor cortex stimulation-induced antinociception., (Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.)

Motor cortex stimulation (MCS) has been used to treat patients with neuropathic pain resistant to other therapeutic approaches; however, the mechanisms of pain control by MCS are still not clearly understood. We have demonstrated that MCS increases the nociceptive threshold of naive conscious rats, with opioid participation. In the present study, the effect of transdural MCS on neuropathic pain in rats subjected to chronic constriction injury of the sciatic nerve was investigated. In addition, the pattern of neuronal activation, evaluated by Fos and Zif268 immunolabel, was performed in the spinal cord and brain sites associated with the modulation of persistent pain. MCS reversed the mechanical hyperalgesia and allodynia induced by peripheral neuropathy. After stimulation, Fos immunoreactivity (Fos-IR) decreased in the dorsal horn of the spinal cord and in the ventral posterior lateral and medial nuclei of the thalamus, when compared to animals with neuropathic pain. Furthermore, the MCS increased the Fos-IR in the periaqueductal gray, the anterior cingulate cortex and the central and basolateral amygdaloid nuclei. Zif268 results were similar to those obtained for Fos, although no changes were observed for Zif268 in the anterior cingulate cortex and the central amygdaloid nucleus after MCS. The present findings suggest that MCS reverts neuropathic pain phenomena in rats, mimicking the effect observed in humans, through activation of the limbic and descending pain inhibitory systems. Further investigation of the mechanisms involved in this effect may contribute to the improvement of the clinical treatment of persistent pain., (Copyright © 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.)

Recent therapeutic human studies testing transcranial direct current stimulation (tDCS) has shown promising results, although many questions remain unanswered. Translational research with experimental animals is an appropriate framework for investigating its mechanisms of action that are still undetermined. Nevertheless, animal and human studies are often discordant. Our aim was to review tDCS animal studies, examining and comparing their main findings with human studies. We performed a systematic review in Medline and other databases, screening for animal studies in vivo that delivered tDCS. Studies in vitro and using other neuromodulatory techniques were excluded. We extracted data according to Animal Research: Reporting In Vivo Experiments (ARRIVE) guidelines for reporting in vivo animal research. Thus, we collected data on sample characteristics (size, gender, weight and specimen) and methodology (experimental procedures, experimental animals, housing and husbandry, as well as analysis). We also collected data on methods for delivering tDCS (location, size, current and current density of electrodes and electrode montage), experimental effects (polarity-, intensity- and after-effects) and safety. Only 12 of 48 potentially eligible studies met our inclusion criteria and were reviewed. Quality assessment reporting was only moderate and studies were heterogeneous regarding tDCS montage methodology, position of active and reference electrodes, and current density used. Nonetheless, almost all studies demonstrated that tDCS had positive immediate and long-lasting effects. Vis-à-vis human trials, animal studies applied higher current densities (34.2 vs. 0.4 A/m(2), respectively), preferred extra-cephalic positions for reference electrodes (60% vs. 10%, respectively) and used electrodes with different sizes more often. Potential implications for translational tDCS research are discussed.

The clearance of apoptotic cells by phagocytes is a fundamental process during tissue remodeling and resolution of inflammation. In turn, the phagocytosis of apoptotic cells generates signals that suppress pro-inflammatory activation of macrophages. These events occur during the resolution phase of inflammation and therefore the malfunctioning of this process may lead to inflammation-related tissue damage. Here, we demonstrate that the calcium-binding protein S100A9, normally abundant in the cytoplasm of neutrophils and also released by apoptotic neutrophils, is involved in the suppression of macrophages after the uptake of apoptotic neutrophils. Both, spontaneous and induced production of inflammatory species (nitric oxide, hydrogen peroxide and TNF-alpha) as well as the phagocytic activity were inhibited when macrophages were in presence of apoptotic neutrophils, conditioned medium from neutrophil cultures or a peptide corresponding to the C-terminal region of S100A9 protein. On the other hand, macrophages kept in the conditioned medium of neutrophils that was previously depleted of S100A9 were shown to resume the activated status. Finally, we demonstrate that the calcium-binding property of S100A9 might play a role in the suppression process, since the stimulation of intracellular calcium release with ionomycin significantly reversed the effects of the uptake of apoptotic neutrophils in macrophages. In conclusion, we propose that S100A9 is a novel component of the regulatory mechanisms of inflammation, acting side-by-side with other suppressor factors generated upon ingestion of apoptotic cells., (Copyright 2009 Elsevier GmbH. All rights reserved.)

Proteinase-activated receptors (PAR) are widely recognized for their modulatory properties in inflammatory and immune responses; however, their direct role on phagocyte effector functions remains unknown. S100A9, a protein secreted during inflammatory responses, deactivates activated peritoneal macrophages, and its C-terminal portion inhibits spreading and phagocytosis of adherent peritoneal cells. Herein, the effect of PAR1 and PAR2 agonists was investigated on spreading and phagocytosis by adherent peritoneal cells, as well as the ability of murine C-terminal of S100A9 peptide (mS100A9p) to modulate this effect. Adherent peritoneal cells obtained from mouse abdominal cavity were incubated with PAR1 and PAR2 agonists and spreading and phagocytosis of Candida albicans particles were evaluated. PAR1 agonists increased both the spreading and the phagocytic activity, but PAR2 agonists only increased the spreading index. mS100A9p reverted both the increased spreading and phagocytosis induced by PAR1 agonists, but no interference in the increased spreading induced by PAR2 agonists was noticed. The shorter homologue peptide to the C-terminal of mS100A9p, corresponding to the H(92)-E(97) region, also reverted the increased spreading and phagocytosis induced by PAR1 agonists. These findings show that proteinase-activated receptors have an important role for spreading and phagocytosis of adherent peritoneal cells, and that the peptide corresponding to the C-terminal of S100A9 protein is a remarkable candidate for use as a novel compound to modulate PAR1 function.

Motor cortex stimulation oriented by functional cortical mapping is used mainly for treating otherwise intractable neurological disorders, however, its mechanism of action remains elusive. Herein, we present a new method for functional mapping of the rat motor cortex using non-invasive transdural electrical stimulation. This method allows a non-invasive mapping of the surface of the neocortex providing a differentiation of representative motor areas. This study may facilitate further investigation about the mechanisms mediating the effects of electrical stimulation, possibly benefiting patients who do not respond to this neuromodulation therapy.

Epidural motor cortex stimulation (MCS) has been used for treating patients with neuropathic pain resistant to other therapeutic approaches. Experimental evidence suggests that the motor cortex is also involved in the modulation of normal nociceptive response, but the underlying mechanisms of pain control have not been clarified yet. The aim of this study was to investigate the effects of epidural electrical MCS on the nociceptive threshold of naive rats. Electrodes were placed on epidural motor cortex, over the hind paw area, according to the functional mapping accomplished in this study. Nociceptive threshold and general activity were evaluated under 15-min electrical stimulating sessions. When rats were evaluated by the paw pressure test, MCS induced selective antinociception in the paw contralateral to the stimulated cortex, but no changes were noticed in the ipsilateral paw. When the nociceptive test was repeated 15 min after cessation of electrical stimulation, the nociceptive threshold returned to basal levels. On the other hand, no changes in the nociceptive threshold were observed in rats evaluated by the tail-flick test. Additionally, no behavioral or motor impairment were noticed in the course of stimulation session at the open-field test. Stimulation of posterior parietal or somatosensory cortices did not elicit any changes in the general activity or nociceptive response. Opioid receptors blockade by naloxone abolished the increase in nociceptive threshold induced by MCS. Data shown herein demonstrate that epidural electrical MCS elicits a substantial and selective antinociceptive effect, which is mediated by opioids.

To date, the endogenous ligands described for cannabinoid receptors have been derived from membrane lipids. To identify a peptide ligand for CB(1) cannabinoid receptors, we used the recently described conformation-state sensitive antibodies and screened a panel of endogenous peptides from rodent brain or adipose tissue. This led to the identification of hemopressin (PVNFKFLSH) as a peptide ligand that selectively binds CB(1) cannabinoid receptors. We find that hemopressin is a CB(1) receptor-selective antagonist, because it is able to efficiently block signaling by CB(1) receptors but not by other members of family A G protein-coupled receptors (including the closely related CB(2) receptors). Hemopressin also behaves as an inverse agonist of CB(1) receptors, because it is able to block the constitutive activity of these receptors to the same extent as its well characterized antagonist, rimonabant. Finally, we examine the activity of hemopressin in vivo using different models of pain and find that it exhibits antinociceptive effects when administered by either intrathecal, intraplantar, or oral routes, underscoring hemopressin's therapeutic potential. These results represent a demonstration of a peptide ligand for CB(1) cannabinoid receptors that also exhibits analgesic properties. These findings are likely to have a profound impact on the development of novel therapeutics targeting CB(1) receptors.

Calcium-binding protein S100A9 (MRP-14) induces antinociceptive effect in an experimental model of painful sensibility and participates of antinociception observed during neutrophilic peritonitis induced by glycogen or carrageenan in mice. In this study, the direct antinociceptive role of the protein S100A9 in neutrophilic cell-free exudates obtained of mice injected with glycogen was investigated. Mice were intraperitoneally injected with a glycogen solution, and after 4, 8, 24, and 48 hours, either the pattern of cell migration of the peritoneal exudate or the nociceptive response of animals was evaluated. The glycogen-induced neutrophilic peritonitis evoked antinociception 4 and 8 hours after inoculation of the irritant. Peritoneal cell-free exudates, collected in different times after the irritant injection, were transferred to naive animals which were submitted to the nociceptive test. The transference of exudates also induced antinociceptive effect, and neutralization of S100A9 activity by anti-S100A9 monoclonal antibody totally reverted this response. This effect was not observed when experiments were made 24 or 48 hours after glycogen injection. These results clearly indicate that S100A9 is secreted during glycogen-induced neutrophilic peritonitis, and that this protein is responsible by antinociception observed in the initial phase of inflammatory reaction. Thus, these data reinforce the hypothesis that the calcium-binding protein S100A9 participates of the endogenous control of inflammatory pain.

Objective and Design: In the present study, the effect of a synthetic peptide (H(92)-G(102)) identical to the C-terminus of murine S100A9 (mS100A9p) was investigated on adherent peritoneal cell function., Materials and Methods: For in vitro assays, peritoneal cells were obtained from the abdominal cavity of mice and incubated, with the different concentrations of mS100A9p, for 1 h, and then their spreading and phagocytosis activities were evaluated. For ex-vivo assays, cells obtained from animals treated for 1 h with the peptide were submitted to the mannose-receptor phagocytosis assay. Shorter homologue peptides to the C-terminus of mS100A9p were also evaluated on in vitro phagocytosis assays of Candida albicans particles., Results: mS100A9p reduced both the spreading index and phagocytic activity, in vitro and ex-vivo, independent of the receptor evaluated. The homologue peptide corresponding to the H(92)-E(97) region of mS100A9p, the zinc-binding motif, was responsible for such an effect., Conclusion: These results suggest a modulator effect of the C-terminus of S100A9 protein on the function of adherent peritoneal cells.

Background: We have previously shown that the calcium-binding protein MRP-14 secreted by neutrophils mediates the antinociceptive response in an acute inflammatory model induced by the intraperitoneal injection of glycogen in mice., Aim: In an attempt to broaden the concept that neutrophils and MRP-14 controls inflammatory pain induced by different type of irritants, in the present study, after demonstrating that carrageenan (Cg) also induces atinociception in mice, we investigated the participation of both neutrophils and MRP-14 in the phenomenon., Methods: Male Swiss mice were injected intraperitoneally with Cg and after different time intervals, the pattern of cell migration of the peritoneal exudate and the nociceptive response of animals submitted to the writhing test were evaluated. The participation of neutrophils and of the MRP-14 on the Cg effect was evaluated by systemic inoculation of monoclonal antibodies anti-granulocyte and anti-MRP-14., Results: Our results demonstrate that the acute neutrophilic peritonitis evoked by Cg induced antinociception 2, 4 and 8 h after inoculation of the irritant. Monoclonal antibodies anti-granulocyte or anti-MRP-14 reverts the antinociceptive response only 2 and 8 h after Cg injection. The antibody anti-MRP-14 partially reverts the antinociception observed after 4 h of Cg injection while the anti-granulocyte antibody enhances this effect. This effect is reverted by simultaneous treatment of the animals with both antibodies. After 4 h of Cg injection in neutrophil-depleted mice a significant expression of the calcium-binding protein MRP-14 was detected in the cytoplasm of peritoneal macrophages. This suggests that the enhancement of the effect observed after treatment with the anti-neutrophil antibody may be due to secretion of MRP-14 by macrophages. It has also been demonstrated that endogenous opioids and glucocorticoids are not involved in the antinociception observed at the 4th hour after Cg injection., Conclusion: These data support the hypothesis that neutrophils and the calcium-binding protein MRP-14 are participants of the endogenous control of inflammatory pain in mice despite the model of acute inflammation used.