Hyperthermia alters neurobehavior by affecting cell proliferation and neuronal survival in young male rats.

Maintenance of body temperature within physiological range is critical for the fetal and neonatal development. Hyperthermia is one of the most frequently encountered pediatric complaints and may cause neurological disorders due to neuronal injury. In this study, we aimed to investigate the effects of hyperthermia on behavioral alterations, neuronal survival, apoptosis, and cell proliferation in young male Sprague-Dawley rats. Twenty-one 13-day-old rats were randomly divided into three groups (n = 7 per group). Body temperature was increased to 39°C and 41°C in a hyperthermia induction chamber for 30 min, whereas the animals in control group were maintained at 36°C. Twenty-four hours after hyperthermia, animals were subjected to the open field test, elevated-O-maze test, and grip strength test to assess the locomotor activity, anxiety, and motor function. Neuronal survival, apoptosis, and cell proliferation were investigated in cortex, hippocampal dentate gyrus (DG) and CA1 regions, and corpus callosum (CC). Decreased locomotor activity and motor function and increased anxiety were observed in the hyperthermia groups, and these were more pronounced in the 41°C group. Neuronal survival was significantly decreased in DG, CA1, and CC in the hyperthermia groups (**p < 0.01). Apoptosis was significantly induced in cortex, DG, and CC of the animals exposed to heat (*p < 0.05). In addition, cell proliferation positivity decreased significantly only in DG and CC of the animals exposed to heat (*p < 0.05). Our results suggest that neurobehavioral deficits caused by hyperthermia may be due to the increased apoptosis and neuronal cell death and decreased cell proliferation in the brain of postnatal developing rats.

Cinnamon Polyphenol Extract Exerts Neuroprotective Activity in Traumatic Brain Injury in Male Mice.

BACKGROUND: Cinnamon polyphenol extract is a traditional spice commonly used in different areas of the world for the treatment of different disease conditions which are associated with inflammation and oxidative stress. Despite many preclinical studies showing the anti-oxidative and antiinflammatory effects of cinnamon, the underlying mechanisms in signaling pathways via which cinnamon protects the brain after brain trauma remained largely unknown. However, there is still no preclinical study delineating the possible molecular mechanism of neuroprotective effects cinnamon polyphenol extract in Traumatic Brain Injury (TBI). The primary aim of the current study was to test the hypothesis that cinnamon polyphenol extract administration would improve the histopathological outcomes and exert neuroprotective activity through its antioxidative and anti-inflammatory properties following TBI. METHODS: To investigate the effects of cinnamon, we induced brain injury using a cold trauma model in male mice that were treated with cinnamon polyphenol extract (10 mg/kg) or vehicle via intraperitoneal administration just after TBI. Mice were divided into two groups: TBI+vehicle group and TBI+ cinnamon polyphenol extract group. Brain samples were collected 24 h later for analysis. RESULTS: We have shown that cinnamon polyphenol extract effectively reduced infarct and edema formation which were associated with significant alterations in inflammatory and oxidative parameters, including nuclear factor-κB, interleukin 1-beta, interleukin 6, nuclear factor erythroid 2-related factor 2, glial fibrillary acidic protein, neural cell adhesion molecule, malondialdehyde, superoxide dismutase, catalase and glutathione peroxidase. CONCLUSION: Our results identify an important neuroprotective role of cinnamon polyphenol extract in TBI which is mediated by its capability to suppress the inflammation and oxidative injury. Further, specially designed experimental studies to understand the molecular cross-talk between signaling pathways would provide valuable evidence for the therapeutic role of cinnamon in TBI and other TBI related conditions.

Dose-dependent effects of vitamin 1,25(OH)2D3 on oxidative stress and apoptosis.

Background The purpose of this study is to examine the dose-dependent effects of vitamin 1,25(OH)2D3 on apoptosis and oxidative stress. Methods In this study, 50 male Balb/c mice were used as control and experiment groups. The mice were divided into 5 groups each consisting of 10 mice. Calcitriol was intraperitoneally administered as low dose, medium dose, medium-high dose and high dose vitamin D groups (at 0.5, 1, 5 and 10 µg/kg, respectively), for three times a week during 14 days. At the end of the study, annexin V was measured by enzyme-linked immunosorbent assay method, and total antioxidant capacity and total oxidant status values were measured by colorimetric method in serum. Hematoxylin eosin staining was performed in liver tissues and periodic acid schiff staining was performed in kidney tissues. Results While comparing the results of medium-high dose (5 µg/kg) and high dose (10 µg/kg) vitamin D administration to that of the control group, it was observed that serum antioxidant status and annexin V levels decreased and glomerular mesenchial matrix ratio increased in kidney (p<0.05). In addition to these findings, in the group receiving high dose vitamin D (10 µg/kg), it was observed that the damage to the liver increased together with the the oxidative stress index values (p<0.05). Conclusions As a result, this study was the first in the literature to report that use of high-dose vitamin D (10 µg/kg) results in oxidant effect, rather than being an antioxidant, and causes severe histopathological toxicity in the liver and kidney.

The indirect NMDAR antagonist acamprosate induces postischemic neurologic recovery associated with sustained neuroprotection and neuroregeneration.

Cerebral ischemia stimulates N-methyl-d-aspartate receptors (NMDARs) resulting in increased calcium concentration and excitotoxicity. Yet, deactivation of NMDAR failed in clinical studies due to poor preclinical study designs or toxicity of NMDAR antagonists. Acamprosate is an indirect NMDAR antagonist used for patients with chronic alcohol dependence. We herein analyzed the therapeutic potential of acamprosate on brain injury, neurologic recovery and their underlying mechanisms. Mice were exposed to cerebral ischemia, treated with intraperitoneal injections of acamprosate or saline (controls), and allowed to survive until 3 months. Acamprosate yielded sustained neuroprotection and increased neurologic recovery when given no later than 12 hours after stroke. The latter was associated with increased postischemic angioneurogenesis, albeit acamprosate did not stimulate angioneurogenesis itself. Rather, increased angioneurogenesis was due to inhibition of calpain-mediated pro-injurious signaling cascades. As such, acamprosate-mediated reduction of calpain activity resulted in decreased degradation of p35, increased abundance of the pro-survival factor STAT6, and reduced N-terminal-Jun-kinase activation. Inhibition of calpain was associated with enhanced stability of the blood-brain barrier, reduction of oxidative stress and cerebral leukocyte infiltration. Taken into account its excellent tolerability, its sustained effects on neurologic recovery, brain tissue survival, and neural remodeling, acamprosate is an intriguing candidate for adjuvant future stroke treatment.

Melatonin protects against ischemic heart failure in rats.

Ischemic injury, which occurs as a result of sympathetic hyperactivity, plays an important role in heart failure. Melatonin is thought to have antiatherogenic, antioxidant, and vasodilatory effects. In this study, we investigated whether melatonin protects against ischemic heart failure (HF). In Wistar albino rats, HF was induced by left anterior descending (LAD) coronary artery ligation and rats were treated with either vehicle or melatonin (10 mg/kg) for 4 weeks. At the end of this period, echocardiographic measurements were recorded and the rats were decapitated to obtain plasma and cardiac tissue samples. Lactate dehydrogenase, creatine kinase, aspartate aminotransferase, alanine aminotransferase, and lysosomal enzymes (ß-D-glucuronidase, ß-galactosidase, ß-D-N-acetyl-glucosaminidase, acid phosphatase, and cathepsin-D) were studied in plasma samples, while malondialdehyde and glutathione levels and Na+, K+-ATPase, caspase-3 and myeloperoxidase activities were determined in the cardiac samples. Sarco/endoplasmic reticulum calcium ATPase (SERCA) and caveolin-3 levels in cardiac tissues were evaluated using Western blot analyses. Furthermore, caveolin-3 levels were also determined by histological analyses. In the vehicle-treated HF group, cardiotoxicity resulted in decreased cardiac Na+, K+-ATPase and SERCA activities, GSH contents and caveolin-3 levels, while plasma LDH, CK, and lysosomal enzyme activities and cardiac MDA and Myeloperoxidase (MPO) activities were found to be increased. On the other hand, melatonin treatment reversed all the functional and biochemical changes. The present results demonstrate that Mel ameliorates ischemic heart failure in rats. These observations highlight that melatonin is a promising supplement for improving defense mechanisms in the heart against oxidative stress caused by heart failure.

Buprenorphine does not aggravate ischemic neuronal injury in experimental focal cerebral ischemia.

Buprenorphine has been increasingly used as maintenance therapy in opioid dependence as an alternative to methadone and other pharmacological therapies. However, available data suggest increased risk of cerebrovascular events in opioid-dependent patients. Therefore, an opioid that provides safety with regard to neurological function should be considered by opioid-dependent patients. The evidence for the in vitro neurotoxic effects of buprenorphine is rapidly increasing. In order to clarify whether buprenorphine is also neurotoxic under the condition of cerebral ischemia in vivo, we applied an acute dose of buprenorphine in a transient model of focal cerebral ischemia in rats. Our study provides preclinical evidence for the usage of buprenorphine during the postoperative period following ischemic events as well as for the maintenance therapy of opioid-dependent patients wherein the risk of cerebrovascular events is increased.

Intravenous TAT-GDNF is protective after focal cerebral ischemia in mice.

BACKGROUND AND PURPOSE: Delivery of therapeutic proteins into tissues and across the blood-brain barrier is severely limited by their size and biochemical properties. The 11-amino acid human immunodeficiency virus TAT protein transduction domain is able to cross cell membranes and the blood-brain barrier, even when coupled with larger peptides. The present studies were done to evaluate whether TAT-glial line-derived neurotrophic factor (GDNF) fusion protein is protective in focal cerebral ischemia. METHODS: Anesthetized male C57BL/6j mice were submitted to intraluminal thread occlusion of the middle cerebral artery. Reperfusion was initiated 30 minutes later by thread retraction. Laser Doppler flow was monitored during the experiments. TAT-GDNF, TAT-GFP (0.6 nmol each), or vehicle was intravenously applied over 10 minutes immediately after reperfusion. After 3 days (30 minutes of ischemia), animals were reanesthetized and decapitated. Brain injury was evaluated by histochemical stainings. RESULTS: Immunocytochemical experiments confirmed the presence of TAT-GDNF protein in the brains of fusion protein-treated nonischemic control animals 3 to 4 hours after TAT fusion protein delivery. TAT-GDNF significantly reduced the number of caspase-3-immunoreactive and DNA-fragmented cells and increased the number of viable neurons in the striatum, where disseminated tissue injury was observed, compared with TAT-GFP- or vehicle-treated animals. CONCLUSIONS: Our results demonstrate that TAT fusion proteins are powerful tools for the treatment of focal ischemia when delivered both before and after an ischemic insult. This approach may be of clinical interest because such fusion proteins can be intravenously applied and reach the ischemic brain regions. This approach may therefore offer new perspectives for future strategies in stroke therapy.