大鼠全脑缺血对再灌注海马区NO含量和Bcl-2表达的影响

Effects of global cerebral ischemic precondition on NO content and Bcl-2 expression in reperfusion of hippocampus

[目的]探讨全脑缺血预处理对再灌注海马区NO含量和Bcl-2表达的影响。[方法]将72只Wistar大鼠随机分为假手术组、脑缺血组和脑缺血预处理组。假手术组:仅暴露4条血管。脑缺血组:四动脉阻断法,全脑缺血10 min。脑缺血预处理组:全脑缺血预处理3 min,再灌注24 h后再次全脑缺血10 min。所有动物均于末次脑缺血再灌注后12、24、48和72 h取脑组织海马区,硝酸还原酶法检测NO2./NO3.含量,间接反应NO含量;免疫组化方法测定海马区Bcl-2表达。[结果]与假手术比较,脑缺血组和脑缺血预处理组NO含量明显增加,脑缺血组NO含量在48 h达到高峰,72 h出现回落;脑缺血预处理组NO含量在各时间点的变化趋势不明显,与脑缺血组在48和72 h比较差异性有显著性意义(P<0.05,P<0.01)。脑缺血组和脑缺血预处理组Bcl-2表达与假手术组比较明显升高;脑缺血组Bcl-2表达24 h达到高峰,48 h开始减少;脑缺血预处理组Bcl-2表达在12 h表达开始增加,48 h达到高峰,72 h开始减少;在48和72 h,脑缺血预处理组Bcl-2表达明显高于脑缺血组(P<0.05,P<0.01)。[结论]脑缺血预处理引起的NO含量增加,可能与Bcl-2上调表达增加及高峰延迟具有一定相关性。

[ Objective] To observe the effects of global cerebral ischemic precondition on NO content and Bcl-2 expression in the reperfusion of the hippocampus. [ Methods] Seventy -two rats were randomly divided into three groups. The rats shamoperated were only explored four vessels, and global ischemia was induced by occluding four vessels for 10 minutes. In ischemic precondition group,the rats firstly subjected 3 -min global ischemia and then after 24 hours,repeated ischemia sustained for 10 minutes. At 12,24,48 and 72 h after reperfusion,the hippocampus was removed. The NO content and Bcl- 2 expression of hippocampus were respectively measured by the method of nitrate reductase and immunohistochemistry. [ Results] Comparing with sham -operated group,NO content enhanced in global ischemic or ischemia precondition group. In ischemic group,the NO content remarkably increased in 48 h and decreased in 72 h, and was significant higher at 48 h and 72 h comparing with ischemic precondition group （P 〈 0.05,P 〈 0.01 ）. The expressions of Bcl -2 in global ischemic and ischemia precondition groups were higher than sham -operated group. In ischemic group, Bcl -2 expression was remarkably increasing at 24 h and decreasing at 48 h （ P 〈 0. 05, P 〈 0.01 ）, but in ischemic precondition group, it increased at 48 h and decreased at 72 h. Bcl - 2 expression was significant lower in ischemic group than that in ischemic precondition group at 48 h and 72 h （P 〈0. 05 ; P 〈0.01 ）. [ Conclusion] In some extent,the increase of NO content may be related with up - regulated expression of Bcl - 2 and delayed peak level in ischemic precondition.