The changes of Notch signaling in hippocampus after cerebral ischemic precondition

Objective: To investigate the changes of Notch signaling pathway in cerebral ischemic tolerance induced by cerebral ischemic preconditioning.Methods: Sixty adult male SD rats were randomly divided into 2 groups(n = 30) : normal control group(group C) and cerebral ischemic preconditioning group(group P).Group C received no treatment. Group P received cerebral ischemic preconditioning with the right middle cerebral artery occlusion for 20 min,followed by 24 h of reperfusion.Cerebral ischemia and reperfusion mode was induced by unilateral middle cerebral artery occlusion for 120 min,followed by 24 h of reperfusion.Notch intracellular domain(NICD) protein expression was determined by Western blot and expression of the Notch pathway signaling molecules of right hippocampus by real-time quantitative PCR before ischemia and 24h of reperfusion.The neurological deficit score was graded at 24 h of reperfusion.The infarct volumes were then determined after evaluation of the neurological deficit score.Results: Compared with group C,the protein expression of Notch1mRNA,Notch4mRNA and NICD were up-regulated in group P before ischemia(P 0.05);NICD expression was up-regulated at 24 h of reperfusion compared before ischemia in both groups.Compared with group C, NICD expression was down-regulated,the percentage of infarct volume and neurological deficit score was decreased at 24 h of reperfusion in group P(P 0.05).Conclusion: Notch signaling pathway may be associated with brain ischemic tolerance induced by cerebral ischemic preconditioning.