p38MAPK在脑缺血后处理大鼠海马区的表达与意义

Expression and significance of p38MAPK in hippocampus following cerebral ischemic postconditioning in rats

目的观察脑缺血后处理大鼠海马区神经元p38MAPK表达变化,探讨脑缺血后处理的脑保护机制。方法将96只雄性SD大鼠随机均分为假手术组(Sham组)、脑缺血组(IR组)、脑缺血后处理组(IpostC组)。Sham组只切开头部皮肤不电凝,分离颈总埋线不夹闭。IR组采用改良的Pulsinelli四血管闭塞(4-VO)法制作全脑缺血大鼠模型,缺血时间20min;IpostC组于IR组恢复再灌注前给予再灌注15s/缺血15s,重复3次处理。每组又按恢复再灌注后6h、24h、48h、72h分为4个亚组(每个亚组8只大鼠)。应用光镜观察各组大鼠海马区神经元形态变化;免疫组织化学染色和Western Blot检测海马区磷酸化p38MAPK表达情况。结果 IR组大鼠海马区神经元结构损伤严重,各时间点神经元坏死率增加,神经元磷酸化p38MAPK表达增多,差异有统计学意义(P<0.05);与IR组比较,IpostC组大鼠海马区神经元结构损伤明显改善,各时间点神经元坏死率下降,神经元磷酸化p38MAPK表达明显增多,差异有统计学意义(P<0.05)。结论脑缺血后处理对全脑缺血再灌注损伤具有保护作用。

Objective To observe the expression change of p38MAPK in hippocampus neurons and investigate the brain protecting mechanism following cerebral ischemic postconditioning in rats. Methods 96 male SD rats were randomly divided into three groups： sham group, global cerebral ischemia group and cerebral ischemic postconditioning group. The rats in sham group re- ceived head skin cut, no electric coagulation and carotid separation with no embed wire clip. The model of cerebral ischemia was es- tablished by using improved pulsinelli four vessels block （4-VO）, and the time of ischemia was 20 minutes. The rats in ischemic postconditioning group were treated with 3 times reperfusion（15s）/ischemia（15s） before reperfusion. Each group was divide into four subgroups （each with 8 rats） according to reperfusion after 6h, 24h, 48h and 72h. We used HE staining under light microscope to observe variation of neurons form and immunohistochemistry and Western blot to test the expression of p38MAPK. Results The neurons structure of the cerebral iscbemia group was damaged, neuron necrosis rate and the expression of phosphorylated p38MAPK increased at each time point,the differences were statistically signifieant（P〈O. 05）. Compared with cerebral ischemia group, the neurons structure in the cerebral ischemic postconditioning group were ameliorate damaged, neuron necrosis rate and the expression of phosphorylated p38MAPK were decreased at each time point, the difference was statistically significant（P〈0. 05）. Conclusion Cerebral ischemic posteonditioning have endogenous nerve protective effect in cerebral ischemia reperfusion injury, the mechanism may be related to the decrease of the expression of D38MAPK.