摘要目的 通过检测肢体远隔缺血后适应(limb ischemic postconditioning, LIP )后p-Akt蛋白及胱天蛋白酶-9和Bcl-2 mRNA表达,探讨磷脂酰肌醇3激酶(phosphatidyl inositol 3 kinase, PI3K )/Akt通路在LIP保护大鼠局灶性脑缺血再灌注损伤中的作用.方法 42只Wistar大鼠随机分为假手术组、脑缺血再灌注组和LIP组.缺血再灌注组和LIP组均采用线栓法制作大脑中动脉缺血再灌注模型. LIP组在脑缺血2 h后再灌注前实施3个循环健侧股动脉LIP(5 min缺血/5 min再灌注).采用2,3,5-氯化三苯基四氮唑染色测定脑梗死体积,免疫组化染色法检测p-Akt蛋白表达,原位杂交法检测胱天蛋白酶-9和Bcl-2 mRNA表达.结果 与脑缺血再灌注组比较,LIP组脑梗死体积显著缩小(P<0.05),p-Akt蛋白和Bcl-2 mRNA表达水平显著增高(P均<0.05),胱天蛋白酶-9 mRNA表达水平显著降低(P<0.05).结论 LIP可缩小局灶性脑缺血再灌注大鼠脑梗死体积,其机制可能与上调p-Akt蛋白和Bcl-2 mRNA表达以及下调胱天蛋白酶-9 mRNA表达有关,提示LIP可通过PI3K/Akt通路减轻脑缺血再灌注损伤.

abstractsObjective To investigate the role of phosphatidyl inositol 3 kinase (PI3K)/Akt pathway in the protection of focal cerebral ischemia reperfusion injury in rats with limb ischemic postconditioning (LIP) by detecting the expression levels of p-Akt protein, and caspase-9 and Bcl-2 mRNAs after remote LIP. Methods Forty-two Wistar rats were randomly assigned to 3 groups: sham operation, ischemia-reperfusion (IR) and LIP groups. The middle cerebral artery ischemia-reperfusion injury model was induced by the suture method in the IR group and the LIP group. In the LIP group, three circulatory LIP ( 5 min ischemia/5 min reperfusion) in the contralateral femoral artery were performed before reperfusion 2 h after cerebral ischemia. Infarct volume was measured by 2,3,5-triphenyltetrazolium chloride staining. The expression of p-Akt protein was detected by immunohistochemical staining and the expression levels of cystin-9 and Bcl-2 mRNAs were detected by in situ hybridization. Results Compared with the IR group, the infarct volume in the LIP group was significantly reduced ( P<0.05). The expression levels of p-Akt protein and Bcl-2 mRNA significantly increased (all P<0.05), and the expression level of caspase-9 mRNA significantly decreased (P<0.05). Conclusions LIP can reduce the volume of cerebral infarction in focal cerebral ischemia-reperfusion injury in rats. Its mechanism may be involved in up-regulation of p-Akt protein and Bcl-2 mRNA expression and down-regulation of caspase-9 mRNA expression, suggesting that LIP can alleviate cerebral ischemia-reperfusion injury through PI3K/Akt pathway.