rAAV+HO-1基因对慢性脑缺血大鼠认知能力和氧化应激的影响

目的:研究从重组腺相关病毒介导血红素氧合酶-1(rAAV+HO-1)基因对大鼠慢性脑缺血认知能力改变和抗氧化应激作用。方法:成年雄性Wistar大鼠45只,每组各15只,随机分为假手术组(SH)、缺血2月组(2-VO),缺血2月+HO-1治疗组(2-VOH)。各组在脑立体定位仪下定位大鼠海马部位,2-VOH组缓慢注射rAAV+HO-1基因2μl,余组注入等量生理盐水。7 d后,采用永久节扎双侧颈总动脉方法制备慢性脑缺血动物模型。大鼠慢性缺血8周后,Morris水迷宫检测大鼠空间学习能力,Western blotting检测大鼠海马组织HO-1蛋白表达水平的变化,酶学法检测大鼠海马SOD活性、MDA含量、NO水平改变。结果:2-VO组大鼠认知水平下降与SH组比较,差异有统计学意义(P<0.01),2-VOH组比2-VO组逃避潜伏期明显减少,空间探索试验穿过平台次数增多,差异具有统计学意义(P<0.01),2-VOH组HO-1蛋白水平表达与2-VO组对比有统计学差异(P<0.01),2-VOH组与2-VO组对比SOD活性增多、MDA含量和NO水平下降,有统计学差异(P<0.05),2-VOH组与SH组SOD活性、MDA和NO含量无统计学差异(P>0.05)。结论:海马注射重组腺相关病毒介导HO-1基因,能够使慢性脑缺血大鼠海马组织HO-1蛋白水平表达升高,增加SOD活性,降低MDA、NO含量,减少氧化应激损伤,一定程度上改善大鼠空间认知学习能力。

Effect of Heme Oxygenase-1 Gene on Cognitive Function and Oxidative Stress During Chronic Cerebral Ischemia in Rats

Objective:To investigate the effect of heme oxygenase-1(HO-1) gene transfected by a recombinant adeno-associated virus vector injected in rats hippocampus on cognitive function and oxidative stress during chronic cerebral ischemia(CCI).Methods:Thirty male Wistar rats were divided into sham operation group(SH),two-month CCI group(2-VO) and two-month CCI HO-1 group(2-VOH).The HO-1 gene was injected into hippocampus in 2-VOH group.Seven days later,CCI was induced by permanent occlusion of bilateral common carotid arteries in rats.Learning and memory ability was evaluated by Morris water maze(MWM).After 8 weeks,the level of HO-1 protein in hippocampus was determined with Western blotting.SOD and MDA Test Kit was used to test levels of MDA,NO and activities of SOD in hippocampus.Results:The ability of rats at two months after ligation of bilateral common carotid arteries was significantly lower in 2-VO group than that in SH group(P<0.01);In the 2-VOH group,the escape latency was significantly shorter than that in 2-VO group(P<0.01);The expression of HO-1 protein was very low in SH and 2-VO group,but it was significantly increased in 2-VOH group(P<0.01);SOD activity was up-regulated and MDA,NO levels were downregulated in the hippocampus in 2-VOH group compared to the 2-VO rats(P<0.05).Conclusion:These results indicate that HO-1 gene transfected by a recombinant adeno-associated virus vector can improve rats cognitive function and reduce oxidative stress during chronic cerebral ischemia.