亚低温对大鼠脑缺血/再灌注海马神经元p-JNK,AIF的影响

目的 通过动态观察亚低温对SD大鼠全脑缺血海马神经元半胱氨酸蛋白激酶-3(Caspase-3),凋亡诱导因子(AIF),p-JNK表达的影响,探讨亚低温对脑保护的可能机制.方法 10～12周龄的成年雄性SD大鼠,参照Pulsinelli 等1]的四血管阻断法制作全脑缺血模型,随机分为假手术组,全脑缺血再灌损伤组,亚低温再灌注组,每组根据再灌注不同时间点(2 h,1 d,3 d,7 d)制取海马标本,观察其组织形态学变化;免疫组化检测AIF,p-JNK;TUNEL染色检测海马区神经元凋亡;Caspase-3荧光活性检测.结果 假手术组各时间点无变化,缺血再灌注两组海马神经元凋亡在CA1区都从再灌注2 h开始,且在1 d达到高峰后回落,其中亚低温组在(1 d,3 d)明显降低了Caspase-3、AIF、p-JNK的活性,增加了存活细胞(P<0.05).结论 亚低温可显著减少SD大鼠缺血性海马神经元再灌注后凋亡的发生,其机制可能与抑制海马P-JNK的活化,减弱Caspase-3活性,同时通过非Caspase-3通路减少AIF的表达相关.

Effects of mild hypothermia on P-JNK,AIF of rat hippocampus neuron treated with cerebral ischemia-reperfusion

Objective To investigate the effect of mild hypothermia on levels of easpase-3,apoptosis inducing factor(AIF)phosphorylated C-jun-N-termined Kinase(P-JNK)in hippocampus neuron of SD rats treated with cerebral ischemia-reperfusion.Methods Male SD rats were randomly divided into three groups:sham group(group SH),ischemia-reperfusion group(group IR)and mild hypothermia reperfusion group(group HIR). Ischemia-reperfusion injury model was established in groups SH and HIR.Rats were killed at 2 h,1 d,3 d,7 d after reperfusion respectively,and hippocampus samples were propared.AIF was detected with immunohistochemistry.The apoptosic neurons were counted using TUNEL method,and caspase-3 activity was measured by immunonuorescence.Results The levels of AIF,the amount of apoptosic neurons and caspase-3 activity did not change in different time-points in group SH,but increased from 2 h after reperfusion,reaching to the peak at 1 ost-reperfusion day and declining then in groups IR and HIR.The increasing magnitude of Caspase-3,AIF,P-JNK and nueron apoptosis was lower in group HIR than in group IR (P<0.05).Conclusion Mild hypothermia significantly reduces apoptosis of ischemic hippocampus neurons treated with ischemia-reperfusion in SD rats,probably via suppressing P-JNK and caspase-3,and reducing AIF through non-caspase-3 pathway.