白藜芦醇预处理对局灶性脑缺血/再灌注大鼠海马CA1区神经元凋亡的保护作用和机制

摘要

目的 探讨白藜芦醇(resveratrol,Res)预处理对局灶性脑缺血/再灌注大鼠海马CA1区神经元凋亡的保护作用及其机制.方法 ♂SD大鼠60只,随机分为假手术组(Sham)、缺血/再灌注组(I/R)、白藜芦醇预处理组 ( Res+I/R),每组20只.采用线栓法阻断大脑中动脉血供90 min,拔出栓线造成局部脑区缺血/再灌注损伤.Res+I/R组缺血前1 h腹腔注射白藜芦醇(30 mg·kg-1).缺血/再灌注后第5天,TUNEL法原位标记海马CA1区凋亡的神经元细胞,免疫组化法检测海马CA1区PI3K、p-Akt及Caspase-3的表达.结果 TUNEL染色结果显示,与I/R组相比较,白藜芦醇预处理明显减少脑缺血/再灌注损伤所引起的大鼠海马CA1区神经元凋亡(P<0.05);免疫组织化学结果显示,与I/R组相比,白藜芦醇预处理使海马CA1区PI3K、p-Akt表达明显增多(P<0.05),Caspase-3表达明显减少(P<0.05).结论 缺血前1 h白藜芦醇预处理对局灶性脑缺血大鼠海马CA1区神经元凋亡具有保护作用,其主要作用机制可能是通过激活PI3K-Akt信号通路进而抑制凋亡相关蛋白Caspase-3的表达有关.%Aim To explore the proteetive effects of the preconditioning with resveratrol on focal cerebral ischemia-re perfusion induced neuronal apoptosis in hippocampus CA1 region of rats. Methods Sixty Sprague-Davvley rats were randomly divided into sham group, ischemia-re perfusion group ( 1/R ) and resveratrol preconditioning ischemia-re perfusion group ( Res + 1/R ). Fach group had 20 raLs. The middle cerebral artery in raLs was occluded for 90 min by an intraluminal filament and then reperfused to cause transient focal cerebral ischemia. In the Res + 1/R group, Lhe resveratrol ( 30 mg · kg~1 ) was injected intraperitoneally 1 h before ischemia. The apoptotic neurons in the CA1 region were measured by TUJNEL staining at Day 5 after reper-fusion. The expressions of P13K, phospho-Ak1 proteins, and Caspase-3 proteins in the CA1 region were examined by immunohistochemistry staining. Results The results of TUNEL staining showed that, compared with 1/R group, preconditioning with resveratrol significantly reduced the number of TUNEL-positive neurons in the hippocampal CA1 pyramidal layer induced by cerebral ischemia ( P <0. 05 ). The resuks of immunohistochemistry showed that the expression of P13K and phospho-Akt proteins in the hippocampal CA1 region of Res +1/R group was significantly higher than that of 1/R group ( P <0. 05 ). However, resveratrol pretreatment significantly reduced the expression of Caspase-3 protoin ( P <0. 05 ). Conclusion Theresuks suggest that preconditioning with resveratrol 1 h before ischemia possesses neuroprotective effects on focal cerebral ischemia-re perfusion induced neuronal apoptosis. The neuroprotective mechanism of resveratrol may attribute to activating P13K-Akt signal pathway and inhibiting the expression of Caspase-3 protein.