缺血预处理减轻沙土鼠脑缺血再灌注损伤与海马CA1区p-p38MAPK表达的关系

The relationship between ischemic preconditioning alleviating cerebral ischemic-reperfusion injury and the level of activated p38MAPK in hippocampal CA1 regions after cerebral ischemic-reperfusion in gerbils

目的:研究脑缺血预处理减轻沙土鼠脑缺血再灌注损伤与海马CA1区磷酸化p38MAPK(p-p38MAPK)含量之间的关系。方法:采用双侧颈总动脉夹闭造成前脑缺血的动物模型。动物随机分为假手术组(SH组)、预缺血组(IA组,前脑缺血3min)、缺血再灌注组(IR组)、预处理组(IP组)。后3组末次缺血后再分为再灌注15min、2h、6h、1天和5天时间点,每时间点8只动物。前4亚组用免疫组化法测定海马CA1区p-p38MAPK含量。再灌注1天、5天2亚组观察行为学变化和海马CA1区形态学存活细胞数目。结果:IA组、IR组、IP组沙土鼠海马CA1区再灌注15min、2h、6h和1天p-p38MAPK表达均多于SH组,差异有统计学意义(P<0.01);IR组沙土鼠海马CA1区再灌注15min、2h、6h和1天p-p38MAPK表达均多于IA组,差异有统计学意义(P<0.01);IP组沙土鼠海马CA1区再灌注15min和2hp-p38MAPK表达多于IA组,差异有统计学意义(P<0.05),再灌注2h、6h和1天p-p38MAPK表达较IR组下降,差异有统计学意义(P﹤0.05)。IA组与SH组沙土鼠行为学改变无统计学意义(P>0.05);IR组沙土鼠再灌注1天和5天探索活动均较IA组增多,差异有统计学意义(P<0.01);IP组沙土鼠再灌注1天、5天探索活动均少于IR组,差异有统计学意义(P<0.01)。IR组沙土鼠海马CA1区再灌注1天和5天存活神经元少于IA组,差异有统计学意义(P<0.01);IP组沙土鼠海马CA1区再灌注5天存活神经元多于IR组,差异有统计学意义(P<0.01)。结论:3min预缺血可引起海马CA1/3区p-p38MAPK水平轻度升高,但能降低24h后5min缺血再灌注引起的海马CA1区p-p38MAPK水平的上升程度。同时缺血预处理减少海马CA1区神经元死亡,并改善沙土鼠行为学变化。

Objective：To study the relationship of the level of phospho-p38MAPK （p-p38MAPK） and the number of survival neurons in hippocampal CA1 regions by ischemic preconditioning（IP） after cerebral ischemic-reperfusion（IR）. Methods：The model of ischemic-preconditioning in gerbil was established. The animals were randomly allocated into SH group,ischemia in advance group （IA group）,IR group and IP group. After the last ischemia,the animals of the last three groups were respectively further allocated into subgroups of 15 rain,2 h,6 h, 1 d and 5 d after reperfusion with 8 animals in each subgroup. The p-p38MAPK in hippocampal CA1 regions was detected by immunohistochemistry and semiquantitive analyzed using Leica Qwin image analysis system in the former 4 subgroups. The behavioral and morphologic changes were detected in last 2 subgroups. The myringa temperature of gerbils sustained at （37i-0.5） ~C from the beginning of ischemia to recovery from anesthesia. Results：There was few p-p38MAPK detected in hippocampal CA1 regions in SH group. The level of p-p38MAPK in hippocampal CA1 region in IA group was significently higher than that of SH group,but significently lower than that of IR group at 15 min,2 h,6 h and 1 d respectively. The level of p-p38MAPK in hippocampal CAI region in IP group was significently higher than that of IA group at 15 min and 2 h respectively,but was remarkably lower than that of IR group at 15 min,2 h,6 h and 1 d respectively. The behavioral examination showed that gerbils scrawed more actively in IR group at 1 d and 5 d and in IP group at 1 d than those of SH group. Gerbils in IP group scrawed much less actively at 1 d and 5 d than those of IR group. The survival neurons in hippocampal CA1 region of IR group and IP group were less than those of SH group at 1 d and 5 d respectively. The survival neurons of hippocampal CA1 region in IP group were significently more than those of IR group at 1 d and 5 d respectively,but less than those of IA group at 5 d after reperfusion. Conclusious：The level of p-p38AMPK in hippocampal CA1 increased after 3 min IR,and it could reduced the level of p-p38MAPK after another longer time IR after 1 d. IP reduced hippocampal CA1 neurons death and attenuated behaveral changement after longer time IR.