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

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。

Protective effects of preconditioning with resveratrol on focal cerebral ischemia/reperfusion induced neuronal apoptosis in rat hippocampal CA1 region

Aim To explore the protective effects of the preconditioning with resveratrol on focal cerebral ischemia-reperfusion induced neuronal apoptosis in hippocampus CA1 region of rats.Methods Sixty Sprague-Dawley rats were randomly divided into sham group,ischemia-reperfusion group(I/R) and resveratrol preconditioning ischemia-reperfusion group(Res+I/R).Each group had 20 rats.The middle cerebral artery in rats was occluded for 90 min by an intraluminal filament and then reperfused to cause transient focal cerebral ischemia.In the Res+I/R group,the resveratrol(30 mg·kg-1) was injected intraperitoneally 1 h before ischemia.The apoptotic neurons in the CA1 region were measured by TUNEL staining at Day 5 after reperfusion.The expressions of PI3K,phospho-Akt proteins,and Caspase-3 proteins in the CA1 region were examined by immunohistochemistry staining.Results The results of TUNEL staining showed that,compared with I/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 results of immunohistochemistry showed that the expression of PI3K and phospho-Akt proteins in the hippocampal CA1 region of Res+I/R group was significantly higher than that of I/R group(P<0.05).However,resveratrol pretreatment significantly reduced the expression of Caspase-3 protein(P<0.05).Conclusion The results suggest that preconditioning with resveratrol 1 h before ischemia possesses neuroprotective effects on focal cerebral ischemia-reperfusion induced neuronal apoptosis.The neuroprotective mechanism of resveratrol may attribute to activating PI3K-Akt signal pathway and inhibiting the expression of Caspase-3 protein.