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

关键词:  全脑缺血  脑缺血预处理  一氧化氮  Bcl-2  海马区

Key words:  global cerebral ischemia  cerebral ischemic precondition  nitric oxide  Bcl-2  hippocampus

摘要:

［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。

Abstract:

［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 sham-operated 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.