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Inflammation and pain are major clinical burdens contributing to multiple disorders and limiting the quality of life of patients. We previously reported that brain electrical stimulation can attenuate joint inflammation in experimental arthritis. Here, we report that non-aversive electrical stimulation of the locus coeruleus (LC), the paraventricular hypothalamic nucleus (PVN) or the ventrolateral column of the periaqueductal gray matter (vlPAG) decreases thermal pain sensitivity, knee inflammation and synovial neutrophilic infiltration in rats with intra-articular zymosan. We also analyzed the modulation of pain and inflammation during aversive neuronal stimulation, which produces defensive behavioral responses such as freezing immobility to avoid predator detection. Electrical stimulation with higher intensity to induce freezing immobility in rats further reduces pain but not inflammation. However, tonic immobility further reduces pain, knee inflammation and synovial neutrophilic infiltration in guinea pigs. The duration of the tonic immobility increases the control of pain and inflammation. These results reveal survival behavioral and neuromodulatory mechanisms conserved in different species to control pain and inflammation in aversive life-threatening conditions. Our results also suggest that activation of the LC, PVN, or vlPAG by non-invasive methods, such as physical exercise, meditation, psychological interventions or placebo treatments may reduce pain and joint inflammation in arthritis without inducing motor or behavioral alterations. [ABSTRACT FROM AUTHOR]

Local tissue reactions provoked by Bothrops venoms are characterized by edema, hemorrhage, pain, and inflammation; however, the mechanisms of tissue damage vary depending upon the species of snake. Here, we investigated the mechanisms involved in the local inflammatory response induced by the Bothrops jararacussu venom (BjcuV). Female Swiss mice were injected with either saline, BjcuV (0.125–8 μg/paw) or loratadine (an H 1 receptor antagonist), compound 48/80 (for mast cell depletion), capsaicin (for C-fiber desensitization), infliximab (an anti-TNF-α antibody), indomethacin (a non-specific COX inhibitor), celecoxib (a selective COX-2 inhibitor) or fucoidan (a P- and L-selectins modulator) given before BjcuV injection. Paw edema was measured by plethysmography. In addition, paw tissues were collected for the measurement of myeloperoxidase activity, TNF-α and IL-1 levels, and COX-2 immunoexpression. The direct chemotactic effect of BjcuV and the in vitro calcium dynamic in neutrophils were also investigated. BjcuV caused an edematogenic response with increased local production of TNF-α and IL-1β as well as COX-2 expression. Both edema and neutrophil migration were prevented by pretreatment with indomethacin, celecoxib or fucoidan. Furthermore, BjcuV induced a direct in vitro neutrophil chemotaxis by increasing intracellular calcium. Therefore, BjcuV induces an early onset edema dependent upon prostanoid production and neutrophil migration. [ABSTRACT FROM AUTHOR]

Abstract: Aim of the study: The latex of Calotropis procera has been used in the traditional medicinal system for the treatment of leprosy, ulcers, tumors, piles and diseases of liver, spleen, abdomen and toothache. It comprises of a non-dialyzable protein fraction (LP) that exhibits anti-inflammatory properties and a dialyzable fraction (DF) exhibiting pro-inflammatory properties. The present study was carried out to evaluate the effect of LP sub-fractions on neutrophil functions and nociception in rodent models and to elucidate the mediatory role of nitric oxide (NO). Material and methods: The LP was subjected to ion exchange chromatography and the effect of its three sub-fractions (LPPI, LPPII and LPPIII) thus obtained was evaluated on leukocyte functions in the rat peritonitis model and on nociception in the mouse model. Results: LP sub-fractions exhibit distinct protein profile and produce a significant decrease in the carrageenan and DF induced neutrophil influx and exhibit anti-nociceptive property. The LP and its sub-fractions produced a marked reduction in the number of rolling and adherent leukocytes in the mesenteric microvasculature as revealed by intravital microscopy. The anti-inflammatory effect of LPPI, the most potent anti-inflammatory fraction of LP, was accompanied by an increase in the serum levels of NO. Further, our study shows that NO is also involved in the inhibitory effect of LPPI on neutrophil influx. Conclusions: Our study shows that LP fraction of Calotropis procera comprises of three distinct sets of proteins exhibiting anti-inflammatory and anti-nociceptive properties of which LPPI was most potent in inhibiting neutrophil functions and its effects are mediated through NO production. [Copyright &y& Elsevier]

Cholera toxin has been traditionally described as the one that does not induce inflammation. It has, however, potent adjuvant and immuno-modulatory activities. Since the adjuvanticity of other compounds is linked to their capacity to induce inflammation, in the present study the pro-inflammatory activity of cholera toxin was investigated. We studied this activity in the following rat models of inflammation: paw edema and neutrophil migration into the peritoneal cavity, and evaluated cholera toxin''s effect on tumor necrosis factor alpha (TNF-α) production by mouse macrophages. We, also, explored the effects of dexamethasone (DEXA) and of two inhibitors of TNF-α production, thalidomide (TAL) and pentoxifylline, on paw swelling. Cholera toxin-induced significant and dose-dependent paw edema, which peaked 48 h after toxin challenge (Cholera toxin2.5μg: 2.39±0.22 ml). Cholera toxin B subunit did not show edematogenic activity. DEXA, TAL and pentoxifylline significantly reduced cholera toxin-induced edema (DEXA0.5mg/kg: 42.6% of inhibition; TAL45mg/kg: 36% of inhibition; pentoxifylline 45mg/kg: 61% of inhibition). Neither cholera toxin nor its B subunit induced neutrophil migration into peritoneal cavities. Cholera toxin stimulated the release of TNF-α by macrophages (cholera toxin10μg: 11.46±0.44 UI/ml). These data provide evidences that cholera toxin exhibits significant pro-inflammatory activity. It also indicates the role of TNF-α upon the pathophysiology of this event based on the inhibitory action of DEXA, TAL and pentoxifylline, and on TNF-α secretion induced by cholera toxin. [Copyright &y& Elsevier]

• Pitavastatin reduces EAE development. • Pitavatatin modulates Treg and Th17 cell differentiation. • Pitavastatin regulates T cell differentiation by inhibiting mevalonate metabolism. While Treg cells are responsible for self-tolerance and immune homeostasis, pathogenic autoreactive Th17 cells produce pro-inflammatory cytokines that lead to tissue damage associated with autoimmunity, as observed in multiple sclerosis. Therefore, the immunological balance between Th17 and Treg cells may represent a promising option for immune therapy. Statin drugs are used to treat dyslipidemia; however, besides their effects on preventing cardiovascular diseases, statins also have anti-inflammatory effects. Here, we investigated the role of pitavastatin on experimental autoimmune encephalomyelitis (EAE) and the differentiation of Treg and Th17 cells. EAE was induced by immunizing C57BL/6 mice with MOG 35-55. EAE severity was determined by analyzing the clinical score and inflammatory parameters in the spinal cord. Naive CD4 T cells were cultured under Treg and Th17-skewing conditions in vitro in the presence of pitavastatin. We found that pitavastatin decreased EAE development, which was accompanied by a reduction of all parameters investigated. Pitavastatin also reduced the expression of IBA1 and pSTAT3 (Y705 and S727) in the spinal cords of EAE mice. Interestingly, the reduction of Th17 cell frequency in the draining lymph nodes of EAE mice treated with pitavastatin was followed by an increase of Treg cells. Indeed, pitavastatin directly affects T cell differentiation in vitro by decreasing Th17 and increasing Treg cell differentiation. Mechanistically, pitavastatin effects are dependent on mevalonate synthesis. Thus, our data show the potential anti-inflammatory effect of pitavastatin on the pathogenesis of the experimental neuroinflammation by modulating the Th17/Treg axis. [ABSTRACT FROM AUTHOR]