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PURPOSE. Mechanical trauma to the immature rodent brain induces a local primary injury and a distant secondary neuroapoptosis. These lesions are associated with glial cell activation, infiltration of immune cells, increased levels of proinflammatory mediators and proteases as part of neuroinflammation. METHODS. Seven-day-old rats were subjected to cortical trauma with a weight-drop device. Animals were sacrificed at defined time points from 2 hours to 21 days and brain tissues were processed for molecular, biochemical and histological analyses. RESULTS. We studied the expression, distribution pattern, time course and cellular localization of two pro-inflammatory mediators (IL-1ß and IL-18) and two proteases (MMP-2 and MMP-9). Apoptotic cell death affected mostly neuronal populations in the cortex, thalamus and caudate nucleus mainly ipsilateral to the injury 6 hours to 5 days after trauma. The involvement of microglia, astroglia and monocytes-macrophages were investigated at the site of primary and secondary damages. They may contribute to acute or delayed trauma-induced neuronal deficit. CONCLUSIONS. Our findings suggest that the interleukins, proteases and microglia/astrocytes are involved in trauma-induced neuroinflammatory response and might serve as a potential therapeutic target.

The first step to treat aneurysmal subarachnoid hemorrhage (SAH) is aneurysmal obliteration under general anesthesia but not treat the SAH itself and the secondary effects. However, the identification of anesthetics with properties that help to attenuate post-SAH brain injury can be useful for improving outcomes of SAH patients. We examined whether 2% isoflurane and 3% sevoflurane posttreatment are protective against early brain injury (EBI) after SAH. This study used 87 8-week-old male CD-1 mice. We induced SAH by endovascular perforation in mice. Animals were randomly divided into 4 groups: sham-operated (n = 16), SAH + vehicle-medical air (n = 26), SAH + 2% isoflurane (n = 22), and SAH + 3% sevoflurane (n = 23). Neurobehavioral function, brain water content and Western blotting were evaluated at 24 h. The expression of sphingosine kinase (SphK), cleaved caspase-3 and cyclooxygenase-2 (COX2) was determined by Western blotting. Cell death was examined by terminal deoxynucleotidyl transferase-mediated uridine 5′-triphosphate-biotin nick end-labeling staining. Both 2% isoflurane and 3% sevoflurane significantly improved neurobehavioral function, and brain edema at 24 h after SAH and attenuated cell death, associated with an increase in SphK1, a decrease in cleaved caspase-3 and COX2. The neuroprotective effects were similar between 2% isoflurane and 3% sevoflurane. These findings suggest that both 2% isoflurane and 3% sevoflurane significantly inhibited EBI by suppressing post-SAH apoptosis and brain inflammation possibly via the SphK1-related pathway.

Exposure to hypobaric hypoxia at high altitude (above 2500 m asl) causes cognitive impairment, mostly attributed to changes in brain perfusion and consequently neuronal death. Enriched environment and voluntary exercise has been shown to improve cognitive function, to enhance brain microvasculature and neurogenesis, and to be neuroprotective. Here we show that high-altitude exposure (3540 m asl) of Long Evans rats during early adulthood (P48-P59) increases brain microvasculature and neurogenesis but impairs spatial and visual memory along with an increase in neuronal apoptosis. We tested whether enriched environment including a running wheel for voluntary exercise (EE) can prevent cognitive impairment at high-altitude and whether apoptosis is prevented. We found that EE retained spatial and visual memory at high altitude, and prevented neuronal apoptosis. Further, we tested whether vascular endothelial growth factor (VEGF) signaling is required for the EE-mediated recovery of spatial and visual memory and the reduction in apoptosis. Pharmacological inhibition of VEGF signaling by oral application of a tyrosine kinase inhibitor (Vandetanib) prevented the recovery of spatial and visual memory in animals housed in EE, along with an increase in apoptosis and a reduction in neurogenesis. Surprisingly, inhibition of VEGF signaling also caused impairment in spatial memory in EE-housed animals reared at low altitude, affecting mainly dentate gyrus microvasculature but not neurogenesis. We conclude that EE-mediated VEGF signaling is neuroprotective and essential for the maintenance of cognition and neurogenesis during high-altitude exposure, and for the maintenance of spatial memory at low altitude. Finally, our data also underlines the potential risk of cognitive impairment and disturbed high altitude adaption from the use of VEGF-signaling inhibitors for therapeutic purposes. This research was supported by the Swiss National Science Foundation [Marie Heim-Vogtlin (MHV) - SNF grant PMPDP3_145480], the Institute of Veterinary Physiology and the Institute of Pharmacology and Toxicology at the University of Zurich, the Institute of Anatomy at the University of Freiburg, and the Institute of Neuroscience at the University of Basque, Spain.

The present study aimed to investigate the effects of microRNA (miR)‑214 on neuroapoptosis induced by propofol and the possible mechanism of its anti‑apoptotic effects. Initially, it was observed that miR‑214 expression was upregulated in propofol‑induced neuroapoptosis rats. Next, propofol‑treated nerve cells were transfected with miR‑214 mimics. The results revealed that miR‑214 overexpression induced apoptosis, inhibited cell proliferation, inhibited cyclin D1 protein expression, promoted caspase‑3 activity and B‑cell lymphoma 2‑associated X protein expression, and enhanced the levels of inflammation factors in nerve cells treated with propofol. In addition, miR‑214 overexpression suppressed phosphoinositide 3‑kinase/protein kinase B (PI3K/Akt) signaling by targeting the activation of phosphatase and tensin homolog (PTEN) and nuclear factor‑κB expression in nerve cells treated with propofol. Treatment with a PTEN inhibitor successfully suppressed the PTEN protein expression and decreased the apoptosis of propofol‑treated nerve cells subsequent to miR‑214 overexpression through PI3K/Akt signaling. In conclusion, the present study data revealed that miR‑214 suppressed propofol‑induced neuroapoptosis through the activation of PI3K/Akt signaling by targeting PTEN expression.

Objective: Unconjugated bilirubin (UCB) may cause neurotoxicity in preterm neonates due to immaturity of UGT1A1 leading to bilirubin accumulation in the brain. Caffeine used in the treatment of apnea of prematurity was reported to decrease mechanical ventilation requirement, the frequencies of bronchopulmonary dysplasia, patent ductus arteriosus, cerebral palsy and neurodevelopmental disorders in very low birth weight infants. However, the effect of caffeine on hyperbilirubinemia was not yet clarified. Methods: We used astrocyte cell cultures obtained from 2-day-old Wistar albino rats via modified Cole and de Vellis method. UCB concentration toxic to 50% of astrocytes, and caffeine concentration increasing cell viability 100% were used in experiments. While no medication was applied to the control group, UCB (50 μM) and caffeine (100 μM) were applied to the bilirubin and caffeine groups for 24 h. Prophylactic and therapeutic caffeine groups were treated with caffeine 4 h before and after UCB exposure. The effects of caffeine were investigated in rat astrocytes exposed to UCB in terms of cell viability, apoptosis, antioxidant defense, proinflammatory cytokines, and Toll-like receptor (TLR)s. Results: Compared to the control group, UCB increased apoptosis, malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, total nitrate/nitrite, and TLR4 levels, and decreased cell viability, catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD) activities, glutathione, and TLR9 levels (for all p

Anesthetic and anti-epileptic drugs used in pediatric and obstetric medicine and several drugs, including alcohol, that are abused by pregnant women, trigger widespread neuroapoptosis in the developing brain of several animal species, including non-human primates. Caffeine (CAF) is often administered to premature infants to stimulate respiration, and these infants are also exposed simultaneously to anesthetic drugs for procedural sedation and/or surgical procedures. Pregnant women who abuse alcohol or other apoptogenic drugs also may heavily consume CAF. We administered CAF to infant mice alone or in combination with alcohol, phencyclidine, diazepam, midazolam, ketamine, or isoflurane, which are drugs of abuse and/or drugs frequently used in pediatric medicine, and found that CAF weakly triggers neuroapoptosis by itself and markedly potentiates the neuroapoptogenic action of each of these other drugs. Exposure of infant mice to CAF + phencyclidine resulted in long-term impairment in behavioral domains relevant to attention deficit/hyperactivity disorder, whereas exposure to CAF + diazepam resulted in long-term learning/memory impairment. At doses used in these experiments, these behavioral impairments either did not occur or were substantially less pronounced in mice exposed to CAF alone or to phencyclidine or diazepam alone. CAF currently enjoys the reputation of being highly beneficial and safe for use in neonatal medicine. Our data suggest the need to consider whether CAF may have harmful as well as beneficial effects on the developing brain, and the need for research aimed at understanding the full advantage of its beneficial effects while avoiding its potentially harmful effects.

Exposure of infant rats or mice to ethanol on a single occasion during the period of rapid synaptogenesis can cause extensive apoptotic neurodegeneration throughout the developing CNS. Prior studies were designed to assess the effects of large doses of ethanol (comparable to heavy binge drinking), whereas in the present study, we sought to determine what magnitude and duration of blood ethanol elevation are required to trigger a minimal neuroapoptotic response. We found that a rise in blood ethanol to a level in the range of 50 mg/dl for a duration of 30 to 45 min was sufficient to trigger a significant neuroapoptosis response deleting approximately 20,000 neurons per infant mouse brain. Since blood ethanol elevations in this range are commonly achieved by humans in a social drinking context, a mother with only a moderate drinking habit might expose her fetus to such elevations on multiple occasions during pregnancy.

Every year millions of young people are treated with anaesthetic agents for surgery and sedation in a seemingly safe manner. However, growing and convincing preclinical evidence in rodents and nonhuman primates, together with recent epidemiological observations, suggest that exposure to anaesthetics in common clinical use can be neurotoxic to the developing brain and lead to long-term neurological sequelae. These findings have seriously questioned the safe use of general anaesthetics in obstetric and paediatric patients. The mechanisms and human applicability of anaesthetic neurotoxicity and neuroprotection have remained under intense investigation over the past decade. Ongoing pre-clinical investigation may have significant impact on clinical practice in the near future. This review represents recent developments in this rapidly emerging field. The aim is to summarise recently available laboratory data, especially those being published after 2010, in the field of anaesthetics-induced neurotoxicity and its impact on cognitive function. In addition, we will discuss recent findings in mechanisms of early-life anaesthetics-induced neurotoxicity, the role of human stem cell-derived models in detecting such toxicity, and new potential alleviating strategies.

Neurotrofini čine familiju signalnih molekula sa brojnim uticajima na rast, preživljavanje, diferencijaciju i sinaptičku plastičnost postmitotskih neurona, kako u adultnom mozgu, tako i u mozgu tokom razvića. Neurotrofini (BDNF, NGF) se sa određenim afinitetom vezuju za Trk receptore, iniciraju njihovu dimerizaciju i autofosforilaciju i na taj način se pokreće aktivacija signalnih puteva kao što su PI3K/Akt i MAPK/ERK. Akt i ERK kinaze imaju ključne regulatorne uloge u mozgu u procesima kao što su neuronalna proliferacija, diferencijacija, razviće, migracija, preživljavanje i dugotrajna sinaptička plastičnost. Aktivan (fosforilisan) Akt štiti ćeliju od apoptoze tako što stimuliše ekspresiju proteina koji favorizuju preživljavanje ćelija i sa druge strane inhibira egzekutorske kaspaze. Aktivacija ERK1/2 kinaze pomoviše preživljavanje, međutim u određenim uslovima ERK1/2 može imati i pro-apoptotske odlike. S obzirom da je uloga neurotrofina u neurotoksičnosti koja je indukovana anestezijom tokom ranog postnatalnog razvića pokazana u nekoliko studija, cilj ove doktorske disertacije je bio da se na molekulskom nivou ispitaju promene u signalnom putu neurotrofina koje nastaju u kori i talamusu postnatalnih pacova nakon primene anestetske doze propofola, kao i da se utvrdi potencijal tretmana da indukuje ćelijsku smrt i/ili promene u sinaptičkoj plastičnosti. Nakon jednokratne primene propofola (25 mg/kg i.p.) ispitana je vremenska i prostorna ekspresija neurotrofina BDNF i NGF, njihovih aktiviranih receptora TrkB, TrkA i p75 receptora, kao i nishodnih kinaza Akt i ERK kod 14 dana starih (PND14) pacova. Ispitan je i potencijal propofolskog tretman da indukuje ćelijsku smrt, praćenjem ekspresije TNF-α, TNFR1, aktivnog fragmenta kaspaze-3, njegovog inhibitora XIAP proteina, kao i transkripcionog faktora NFκB. Finalno je ispitivan potencijal propofolskog tretmana da indukuje promene u ekspresiji markera sinaptičke plastičnosti (MAP-2, drebrina, GAP-43, sinaptofizina, sinukleina-1 i N-kadherina). Promene su praćene u kori i talamusu kao primarnim ciljevima dejstva anestetskog delovanja. Primenom sledećih metoda Western blot analize, RT- i PCR-a u realnom vremenu ispitivane su promene u ekspresiji ciljnih proteina i iRNK, a primenom Fluoro-žad B histološkog bojenja analizirana je pojava neurona u degeneraciji... The neurotrophins are a family of secreted proteins that mediate numerous functions in both the developing and mature nervous system, including growth, survival, differentiation and synaptic plasticity of postmitotic neurons. The binding of neurotrophins (BDNF, NGF) to Trk receptors induces their dimerization which is followed by autophosphorylation of tyrosine residues within the intracellular kinase domain, that leads to the activation of signaling pathways such as the PI3K/Akt and MAPK/ERK pathways. Akt and ERK kinases play a crucial role in regulating various processes in the brain, including neuronal proliferation, differentiation, development, migration, survival and long-term synaptic plasticity. Phosphorylated Akt can protect cells from apoptosis via stimulation of the expression of proteins that favor cell survival and by inhibiting executor caspases. Activation of ERK1/2 generally promotes cell survival, although under certain conditions, ERK1/2 can possess proapoptotic properties. Since several studies have revealed a role for neurotrophins in anesthesia-induced neurotoxicity in the developing brain, the goal of this study was to explore the potential of anesthetic dose of propofol to influence neurotrophic signaling pathway in the cortex and thalamus of 14-day-old (PND14) rats, and also to investigate whether same treatment is able to induce neurodegeneration and/or changes in synaptic plasticity. In this study we monitored the spatial and temporal expression of neurotrophic signaling molecules (BDNF, NGF, TrkA, TrkB, p75, Akt and ERK) in the brain of PND14 Wistar rats after the application of a single propofol dose (25 mg/kg i.p). The potential of propofol treatment to induce cell death was also examined, following the expression of TNF-α, TNFR1, cleaved caspase-3 fragment, XIAP and NFκB. Finally, we investigated the changes in the markers of synaptic plasticity (MAP-2, drebrin, GAP-43, synaptophysin, synuclein-1 and N-cadherin) after the propofol treatment. The structures of interest were the cortex and thalamus as the primary areas of anesthetic actions. Changes of the levels of mRNA and proteins of interest were assessed by RT- or Real Time PCR and Western immunoblot analysis at different time points during the first 24 h after the treatment. Fluoro-Jade B staining was used to follow the appearance of degenerating neurons...

Exposure to general anesthetics and antiepileptics during critical stages of brain development causes significant neurotoxicity to immature neurons. Many animal, and emerging human studies have shown long-term functional sequelae manifested as behavioral deficits and cognitive impairments. Since general anesthetics and antiepileptic drugs are a necessity, current research is focused on deciphering the mechanisms responsible for anesthesia-induced developmental neurotoxicity so that protective strategies can be devised. These agents promote massive and wide-spread neuroapoptosis that is caused by the impairment of integrity and function of neuronal organelles. Mitochondria and endoplasmic reticulum are particularly vulnerable. By promoting significant release of intracellular calcium from the endoplasmic reticulum, anesthetics cause an increase in mitochondrial calcium load resulting in the loss of their integrity, release of proapoptotic factors, functional impairment of ATP synthesis and enhanced accumulation of reactive oxygen species. The possibility that general anesthetics may have direct damaging effects on mitochondria, resulting in the impairment of their morphogenesis, also has been proposed. This review will present evidence that neuronal organelles are critical and early targets of anesthesia-induced developmental neurotoxicity.

Objectives and Aim: This study was designed to analyze the relationship between the expression of c-Fos protein and apoptosis in the hippocampus following propofol administration in infant mice. There are reports that certain drugs, including the general anesthetics applied in pediatrics and obstetrics, could block N-methyl-D-aspartate glutamate receptors and activate γ-aminobutyric acid type A receptors. Furthermore, some anesthetics could trigger neuroapoptosis and the expression of c-Fos in the developing rodent brain. Propofol is a general anesthetic increasingly used in pediatrics and obstetrics, and is reported to be able to interact with both γ-aminobutyric acid type A and N-methyl-D-aspartate glutamate receptors. No adequate evaluations have been available as to whether the dosage of propofol to maintain anaesthesia could trigger the expression of c-Fos and apoptosis. Materials and Methods: Intraperitoneal injections of propofol (50, 100 and 150 mg/kg) or vehicle were administered every 90 minutes (4 times) in infant mice (5–7 days old). 30 minutes after the final administration, the protein expressions of c-Fos and cleaved-caspase-3 in the hippocampus were determined by immunohistochemistry and Western blotting. Results: It was demonstrated that the expressions of cleaved-caspase-3 and c-Fos were upregulated in the hippocampal CA3 region in this study. Conclusions: The upregulated c-Fos expression induced by repeated injections of propofol might evoke neuroapoptosis.