慢性脑缺血对大鼠海马α-分泌酶表达和活性的影响

Effect of chronic brain ischemia on the expression and activity of α-secretase in the hippocampus of rats

目的探讨慢性脑缺血对大鼠海马α-分泌酶的表达和活性的影响。方法双侧颈总动脉结扎制作大鼠慢性脑缺血模型,分别于术后10 d、30 d、90 d和180 d用Y迷宫测试其学习记忆能力;分别用定量PCR和免疫印迹法检测海马α-分泌酶ADAM 10和ADAM 17m RNA的表达和蛋白含量;用荧光法测定海马α-分泌酶的活性。结果 Y迷宫测试显示模型组术后30 d、90 d和180 d所需的电击次数较对照组逐渐增加(P<0.05;P<0.01)。PCR和免疫印迹结果显示,术后30 d、90 d和180 d海马ADAM 10和ADAM 17m RNA表达及其含量明显降低(P<0.05;P<0.01);酶活性检测显示模型组α-分泌酶活性于术后持续性降低,与对照组相比,差异有统计学意义(P<0.05,P<0.01)。结论慢性脑缺血下调海马α-分泌酶表达,并抑制其活性,可能在阿尔茨海默病发病过程中有重要意义。

Objective To investigate the effect of chronic brain ischemia on the expression and activity of α-secretase in the hippocampus of rats. Methods Cerebral blood hypoperfusion rat model by bilateral common carotid artery permanent ligation was made. Y-maze test was conducted at 10 days, 30 days, 90 days and 180 days after operation to examine the spatial learning and memory ability. Real-time PCR and western blotting were used to essay the expression of m RNA and protein level of a disintegrin and metalloproteinase（ADAM） 10 and 17 representing α-secretase in hippocampus, and fluorescence spectrometry was applied to measure activity thereof. Results The numbers of electric stroke since 30 days after operation were significantly higher than rats of control group（P〈0.05, P〈0.01）. The expression of m RNA and protein level of ADAM 10 and ADAM 17 in hippocampus of rats in model group at 30 days, 90 days and 180 days after operation were obviously decreased compared with control group（P〈0.05, P〈0.01）. The average fluorescence values of α-secretase in the hippocampus of rats was decreased obviously and continuity since 10 days after the operation（P 〈0.05, P 〈0.01）. Conclusion The expression of α-secretase in the hippocampus was down-regulation and the activity of that was decreased after chronic brain ischemia, which may play a very important role in early pathogenesis of Alzheimer ’s disease.