人参皂苷Rb1对大鼠脑缺血再灌注损伤中NAIP表达的影响

Effect of Ginsenoside Rb1 on Expression of Neuronal Apoptosis Inhibitory Protein in Cerebral Tissue of Rats Subjected to cerebral ischemic-reperfusion Injury

目的:观察人参皂苷Rb1对神经元凋亡抑制蛋白(neuronal apoptosis inhibitory protein,NAIP)在脑缺血再灌注损伤中表达的影响,探讨人参皂苷Rb1对缺血性脑病的防治机制。方法:线栓法阻断大鼠大脑中动脉2h,再灌注3h～5d制备脑缺血再灌注模型,应用免疫组织化学方法标记NAIP阳性细胞,观察人参皂苷Rb1对NAIP阳性细胞数的影响。结果:缺血再灌注后,缺血半暗带内的NAIP阳性细胞表达增加,海马CA1区等部位的NAIP阳性细胞数量也明显增加,而缺血中心区无NAIP阳性细胞的表达。实验对照组中NAIP阳性细胞数量随再灌注时间延长逐渐升高,12h达到高峰,至5d时NAIP阳性细胞数量表达低于正常水平。实验用药组中NAIP阳性细胞数量在2d时达到高峰,且其高峰值明显高于实验对照组中的高峰值,后随再灌注时间的延长而逐渐下降,至5d时仍处于较高水平。结论:脑缺血再灌注后,NAIP表达增加是脑组织对损伤的一种保护性反应,其对缺血区周围的神经细胞的保护作用更为明显。NAIP在脑组织中的表达具有一定的时间规律性,并且人参皂苷Rb1可能通过上调NAIP的表达发挥对受损脑组织的保护作用。

Objective:To investigate the influence of ginsenoside Rb1 on expression of neuronal apoptosis inhibitory protein(NAIP) in cerebral tissue of rats subjected to cerebral ischemia-reperfusion,and find out the mechanisms of ginsenoside Rb1 on cerebral tissue against cerebral ischemia-reperfusion injury.Methods:The models of cerebral ischemia-reperfusion were induced by blocking right middle cerebral artery occlusion(MCAO) with intraluminal nylon fiber for 2 h and reperfusion for 3 hours to 5 days.These rats were divided into two groups randomLy:experiment control and ginsenoside Rb1 group.Sham-operated rats were regarded as a control group.The immunohistochemical staining was employed to observe the expression of NAIP in cerebral tissues.Results:After cerebral ischemia-reperfusion,the number of NAIP-positive cells in semidarkness zone of ischemia and hippocampus CAI increased.The expression of NAIP became stronger during cerebral ischemia-reperfusion.However,no NAIP-positive cell was observed in the centre of ischemic zone.In experiment control group,the number of NAIP-positive cells peaked at 12 h of reperfusion,and then decreased gradually to the lower than normal level on 5th day of reperfusion.In ginsenoside Rb1 group,the number of NAIP positive cells peaked at 2 d of reperfusion,and then gradually decreased,but it was higher on 5th day of reperfusion.Conclusions:The increased expression of NAIP is protective reaction of brain tissue against injury during cerebral ischemia-reperfusion,especially the nerve cells around ischemic region.The expression of NAIP in brain tissues possesses some time regularity.Up-regulating expression of NAIP is one way of protection of ginsenoside Rb1 on nervous tissue against ischemia-reperfusion injury.