全脑缺血再灌注大鼠额叶、海马、丘脑EGF和NT-4／5的动态表达

The dynamic expression of EGF and NT-4/5 in the frontal lobe,hippocampus and thalamus of rats after cerebral ischemia-reperfusion

目的:探讨全脑缺血再灌注大鼠额叶、海马、丘脑的表皮生长因子(EGF)和神经营养因子-4/5(NT-4/5)含量变化,以揭示EGF和NT-4/5对额叶、海马、丘脑缺血再灌注损伤的动态保护作用。方法:选用Wistar老龄大鼠,雌雄随机分组,对照组5只,实验组分全脑缺血15分钟组,缺血15分钟再灌注1小时、6小时、2天、4天、9天组,每组5只。结果:正常老龄大鼠额叶、海马、丘脑均有少量EGF和NT-4/5表达。额叶仅于再灌注2天EGF表达明显增加;海马于再灌注6小时～4天EGF表达呈持续增加,且4天时其表达呈高峰;丘脑于再灌注2～9天期间,EGF表达也呈持续性增加。额叶缺血再灌注后NT-4/5表达明显减少,于再灌注9天才恢复正常;海马于缺血再灌注后有一过性NT-4/5表达减少,但很快恢复正常并有一定量增加;丘脑仅有一过性NT-4/5表达减少。结论:缺血缺氧时额叶缺乏早期快速的EGF神经保护机制,且在缺血中晚期其神经保护作用也比较有限;海马具有反应快捷、作用持久的EGF神经保护机制;丘脑具有迟发性EGF神经保护机制。额叶和海马具有迟发性NT-4/5神经保护机制,丘脑NT-4/5神经保护机制比较弱。

Objective： To investigate the content change of EGF and NT-4/5 in the the frontal lobe, hippocampus and thalamus of rats after cerebral ischemia-reperfusion, in order to reveal the dynamic protection of EGF and NT-4/5 to cerebellum ischemia-reperfusion injury. Methods ： Wistar senile rats were divided into the control group and the experiment groups at random. The control group included 5. The experimental groups were divided into cerobral ischemia 15 rain group and ischemia-reperfusion 1 h,6 h,2 d,4 d,9 d groups after 15 min ischemia, 5 rats per group. Results： There was all a little expression of EGF and NT-4/5 in the frontal lobe, hippocampus and thafamus of normal senile rats. The frontal lobe was shown evident increase of EGF expression in ischemia-reperfusion 2 d only. The hippocampus was shown continued in- crease of EGF expression during ischemia-reperfusion 6 h to 4 d and the EGF expression was shown a peak in ischemia-reperfusion 4 d. The increase of EGF expression in thalamus continued during ischemia-reperfusion 2-9 d too. The NT-4/5 expression of the frontal brain was clearly reduced after ischemia-reperfusion and returned to normal in ischenfia-reperfusion 9 d. The NT-4/5 expression of hippocampus was shown oneoff reduetion after iscbemia-reperfusion, but the expression qnickly returned to normal and shows a little increase. The thalamus had only one-off reduction of NT-4/5 expression. Conclusion： The frontal lobe lacks of fast neuroprotective mechanism of EGF in early stage of ischemia-reperfusion and it has a limited ncuroprotective effect of EGF in middle and advanced stage. The hippocampus has a fast and long-lasting neuroprotectire mechanism of EGF. The thalamus has a delayed neuroprotective mechanism of EGF. The frontal brain and hippocampus have a delayed neu- roprotective mechanism of NT-4/5. The neuroprotective mechanism of NT-4/5 is weaker in thalamus.