远隔后适应对大鼠脑组织中淀粉样前体蛋白表达的影响

The effects of remote ischemic post-conditioning on expression of amyloid precursor protein in rats following cerebral ischemia and reperfusion

目的研究远隔缺血后适应对大鼠脑缺血再灌注损伤后存在于神经元和神经胶质细胞中的淀粉样前体蛋白(β-amyloid precursor protein,β-APP)的影响。方法应用线栓法制作大鼠大脑中动脉闭塞缺血模型,缺血即刻和再灌注即刻分别给予肢体缺血后适应。应用双侧股动脉夹闭10 min/放开10 min,反复3次进行肢体缺血后适应。实验分为7组:假手术组,单纯缺血再灌注组(4 h、24 h组),缺血再灌注+缺血即刻远隔缺血后适应组(4、24 h组),缺血再灌注+再灌注即刻远隔缺血后适应组(4 h、24 h组),每组4只大鼠。采用免疫荧光方法观察β-APP蛋白表达的部位;采用免疫印迹方法研究β-APP的蛋白表达水平。结果脑缺血组大鼠缺血脑组织β-APP蛋白表达在缺血后不同时间点与假手术组比较差异无统计学意义。但是,可以看出β-APP在大鼠缺血后4 h无升高,缺血后24 h开始升高。给予远隔缺血后适应组与单纯缺血组比较,24 h时缺血即刻给予远隔后适应组,β-APP蛋白水平显著低于对照组(P<0.05)。结论远隔缺血后适应可能会通过降低脑缺血后β-APP蛋白表达水平,从而减轻脑缺血损伤。

Objective To investigate the effects of remote ischemic post conditioning on the expression of amyloid precursor protein（APP） in rats following cerebral ischemia and reperfusion.Methods The focal ischemia and reperfusion rat model was established with suture method.The remote ischemic post-conditioning was performed with bilateral occluding of bilateral femoral arteries for 10 min and reperfusion for 10 min,repeated for 3 times.The rats were divided into 7 groups： sham group（n=4,named S）,control group（n=8,rats were only subjected to focal cerebral ischemia and reperfusion,4 rats were sacrificed at 4 hours after ischemia and another 4 at 24 hours,named C4,C24）,and the experiment groups（n=8,the rats underwent focal cerebral ischemia/reperfusion and remote ischemia post conditioning immediately after cerebral ischemia： 4 rats were sacrificed at 4 hours after ischemia and the other 4 at 24 hours,named I4,I24;n=8,rats underwent focal cerebral ischemia/reperfusion and remote ischemia post conditioning immediately after reperfusion;4 of the rats were sacrificed at 4 hours after ischemia and the other 4 at 24 hours,named R4,R24）.Beta-APP was determined quantitatively by Western blotting.The immunofluorescence was used for the localization of β-APP.Results There were no significant differences between C4,C24 and S groups.But the level of β-APP in the C24 group was increased compared to the S group.Compared to the C24 group,the level of β-APP was significantly decreased in the I24 group（P0.05）.Conclusion Remote ischemic post-conditioning might decrease the level of β-APP induced by cerebral ischemia,resulting in attenuation of cerebral ischemic damage.