Effects Of Mild Hypothermia On Apoptosis And The Expression Of BDNF In Cortical Neuron Following Focal Cerebral Ischemia Reperfusion In Rats

[Objective] To establish modified transient focal cerebral ischemia model in rats, and explore the neuroprotective mechanisms of mild hypothermia.[Methods]Modified middle cerebral artery occlusion models of transient focal cerebral ischemia were established. All the rats were divided into normothermic group and mild hypothermic group. The neurological impairment was evaluated with Neurological Grading Scale. The infarction volume was measured with TTC staining. The pathological changes in brain were studied with HE staining. Apoptosis after focal ischemia was observed with TUNEL staining. The expressions of BDNF were measured with immunohistochemical staining. The cell types were distinguished with BDNF and TUNEL double staining.[Results]Compared to normothermic group, the neurological defect score, the infarct volume and the quantity of apoptotic neurons were significantly decreased, the quantity of BDNF positive neurons was significantly increased in mild hypothermic group. BDNF and TUNEL double staining clearly showed that no neuron contained high level of BDNF in their cytoplasm was TUNEL staining positive.[Conclusions]The modified ischemia-reperfusion focal cerebral ischemic model in rat was reliable for cerebral vascular disease study.Neuroprotective mechanism of mild hypothermia possibly includes upgrading the expression of BDNF, which restrained the neuronal apoptosis, reduced infarct volume and decreased neurological defect signs.