褪黑素对大鼠脑缺血再灌注损伤及胞浆型磷脂酶A_2蛋白表达的影响

目的观察褪黑素在脑损伤时对脑细胞凋亡和胞浆型磷脂酶A2(cPLA2)蛋白的表达及相关介质的影响。方法采用线栓法制作大脑中动脉缺血再灌注模型,将78只雄性Wister大鼠随机分为假手术组(6只)、模型组(36只)、治疗组(36只)。用HE染色和TUNEL法检测各组海马CA1区神经细胞凋亡;用免疫组织化学法检测海马CA1区神经细胞中cPLA2蛋白表达;用ELISA法检测血清中TNF-α和前列腺素E2(PGE2)水平。结果与假手术组比较,模型组不同时间点凋亡细胞及cPLA2蛋白表达增强,且血清中TNF-α和PGE2水平也显著增高(P<0.01)。与模型组比较,治疗组能明显降低海马CA1区细胞凋亡数和cPLA2蛋白表达,同时也能降低血清中TNF-α和PGE2水平(P<0.01)。结论褪黑素对大鼠大脑中动脉缺血再灌注脑损伤有良好的保护作用:降低缺血再灌注后血清中TNF-α和PGE2水平,抑制缺血再灌注后海马CA1区cPLA2蛋白表达。

Effects of melatonin on cerebral injury and expression of cPLA2 protein during cerebral ischemia-reperfusion in rats

Objective To observe the effects of melatonin on cerebral apoptosis and expression of cytosolic phopholipase A2(cPLA2) and related mediators during cerebral injury.Methods Thread occlusion technique was used to make models of middle cerebral artery ischemia-reperfusion(MCA-IR).Seventy-eight male Wistar rats were divided into sham-operated,model and melatonin groups.Neuron apoptosis in rats' hippocampal CA1 of each group was measured by HE and TUNEL staining methods.Expression of cPLA2 protein in neurons of hippocampal CA1 was measured by immuno-histochemical method.The level of TNF-α and PGE2 were measured by ELISA test.Results Compared with sham-operated group,the apoptosis of neurons and expression of cPLA2 protein increased in model group(P<0.01).Compared with model group,the apoptosis of neurons,the expression of cPLA2 protein and the levels of TNF-α and PGE2 in melatonin group were decreased(P<0.01).Conclusions Melatonin has a good protective effect against MCA-IR injury of rats,which might be attributed to decrease in levels of TNF-α and PGE2,and inhibiting the expression of cPLA2 protein.