熊果酸抑制神经细胞凋亡降低局灶性脑缺血再灌注损伤的实验研究

Ursolic Acid Alleviate the Focal Cerebral Ischemia-reperfusion Injury by Inhibiting Neuronal Apoptosis

目的探讨熊果酸不同剂量对脑缺血再灌注损伤的保护作用及其机制。方法采用线栓法复制局灶性脑缺血再灌注大鼠模型,随机分为假手术组、模型组及熊果酸低剂量组(20 mg/kg)、中剂量组(40 mg/kg)、高剂量组(80 mg/kg),每组20只再灌注前30min腹腔注射给药,24 h后行盲法神经功能评分,测定各组脑组织含水量和脑梗死体积;观察神经细胞凋亡并计算凋亡指数(AI),检测脑组织中bcl-2 mRNA、Bax mRNA表达及caspase-3、核转录因子-κB(NF-κB)蛋白表达。结果熊果酸中、高剂量组大鼠神经功能评分较模型组降低,神经功能症状明显改善,脑组织含水量和梗死体积均降低,差异有统计学意义(P<0.05或P<0.01);熊果酸各剂量组神经细胞凋亡状况呈不同程度好转,中、高剂量组AI降低(P<0.05或P<0.01);熊果酸中、高剂量组脑组织Bax mRNA表达下调、bcl-2 mRNA上调、bcl-2/Bax比值升高,caspase-3、NF-κB蛋白表达下调,差异有统计学意义(P<0.05或P<0.01)。结论熊果酸中、高剂量可能通过抑制神经细胞凋亡而起到降低局灶性脑缺血再灌注损伤的作用。

Objective To investigate the protective effects and mechanism of ursolic acid（ UA） on the focal cerebral ischemia-reperfusion（ I/R） injury in rats.Methods The model of focal cerebral I/R was established with Zea-Longa occluding suture.The rats were randomly divided into 5 groups： sham group（ n = 20）,model group（ n = 20）,UA low-dose group（ 20 mg/kg,n = 20）,UA medium-dose group（ 40 mg/kg,n = 20）,UA high-dose group（ 80 mg/kg,n = 20）. The drugs were given by intraperitoneal injection at 30 min before reperfusion. Twentyfour hours after reperfusion,the neurological deficits,ratio of infarct volume,water content of the brain were evaluated.The neurocyte apoptosis were observed and the Apoptosis Index（ AI） was determined.The expression of bcl-2 mRNA,Bax mRNA and caspase-3,NF-κB protein were detected.Results Compared with model group,the neurological scores were significantly decreased in UA medium-dose group and UA highdose group,the ratio of infarct volume and water content of the brain were significantly decreased（ P〈0.05 or P〈0.01）.The neurocyte apoptosis were significantly improved in UA,and the AI were significantly decreased in UA medium-dose group and UA high-dose group（ P〈0.05 or P〈0.01）.The expression of bcl-2 mRNA was significantly up-regulated and the expression of Bax mRNA was significantly down-regulated,the ratio of bcl-2/Bax were significantly increased,the expression of caspase-3,NF-κB protein were significantly down-regulated in UA medium-dose group and UA high-dose group（ P〈0.05 or P〈0.01）.Conclusion UA can alleviate focal cerebral ischemia reperfusion injury by inhibiting neuronal apoptosis.