保护素D1对大鼠全脑缺血再灌注损伤海马Caspase-3表达及神经元凋亡的影响

Effects of Protectin D1 on Hippocampal Caspase-3 Expression and Neuronal Apoptosis following Global Cerebral Ischemia-Reperfusion in Rats

目的评价保护素D1(PD1)对大鼠全脑缺血再灌注损伤海马Caspase-3蛋白表达及神经元凋亡的影响。方法将108只健康成年雄性SD大鼠随机分为3组:假手术组(S组,n=36)仅游离双侧椎动脉和颈总动脉;脑缺血再灌注损伤组(IR组,n=36)和保护素D1组(P组,n=36)采用四血管阻断法建立大鼠全脑缺血再灌注损伤模型。P组于再灌注即刻经侧脑室注入PD1 100 ng,S组和IR组注入等容量生理盐水。各组分别于再灌注2、6、12、24、48、72 h(T1-T6)随机取6只大鼠处死,取海马组织,采用Western-blot法和RT-PCR法检测海马Caspase-3蛋白和Caspase-3 mRNA表达,采用流式细胞仪检测海马神经元凋亡情况。结果与S组比较,IR组、P组海马Caspase-3蛋白和Caspase-3 mRNA表达均上调(P<0.05);与IR组比较,P组海马Caspase-3蛋白和Caspase-3 mRNA表达均下调(P<0.05)。S组各时点均未见神经元凋亡,IR组和P组于T1时凋亡率开始上升,T4时达峰值,T5时开始下降,且P组各时点凋亡率均明显低于IR组(P<0.05)。结论 PD1可抑制大鼠全脑缺血再灌注损伤海马神经元凋亡,其机制可能与下调Caspase-3蛋白和Caspase-3 mRNA表达有关。

Objective To investigate the effects of protectin D1 （PD1）on the expression of hip- pocampal caspase-3 and neuronal apoptosis following global cerebral ischemia-reperfusion（I/R） in rats. Methods One hundred and eight healthy male Sprague-Dawley rats were randomly divided into three groups： sham operation group （group S）,global cerebral I/R group （group IR） and PD1 group （group P） ,with 36 rats in each group. Global cerebral I/R was produced by 4-vessel occlusion technique. In group P,PD1 （100 ng） was injected into cerebral ventricles at the moment of reperfusion. In group S and group IR, rats were given the same volume of normal saline. Six rats in each group were killed after 2,6,12,24,48 and 72 hours of reperfusion （T1-T6）, respec- tively. Hippocampal tissues were obtained to detect the expression of caspase-3 protein and mR- NA using Western blot and RT-PCR, respectively. Neuronal apoptosis was determined by flow cytometry. Results Compared with group S,the expression of hippocampal caspase--3 protein and mRNA significantly increased in group IR and group P（P〈0. 05）. Compared with group IR, the expression of hippocampal caspase-3 protein and mRNA significantly decreased in group P（P〈 0.05）. No neuronal apoptosis was found in group S at all time points. In group IR and group P,neuronal apoptosis rate began to increase at T1, reached the peak at T4,and began to decrease at TS. Compared with group IR, the apoptosis rate significantly decreased in group P at each time point（P〈0.05）. Conclusion PD1 can inhibit hippocampal neuronal apoptosis induced by global cerebral I/R through down-regulation of caspase-3 protein and mRNA expression.