GAD在颞叶癫痫大鼠海马内源性促痫机制中的作用

目的:探讨GAD65、GAD67在颞叶癫痫发生后海马内源性促痫机制中的作用。方法:112只雄性SD大鼠随机分为实验组(n=70)与对照组(n=42),实验组大鼠选用海人酸腹腔注射法建立颞叶癫痫模型,对照组大鼠腹腔注射无菌生理盐水。选取腹腔注射后3小时、6小时、12小时、24小时、48小时、7天、30天为研究的时间点,颞叶海马的CA1区、CA3区、齿状回为研究部位。腹腔给药后每天观察大鼠的行为学变化,大鼠处死前进行EEG描记。用原位杂交方法检测不同时间点海马不同区域GAD65、GAD67mRNA的表达,免疫组织化学法检测GAD65、GAD67蛋白的表达。结果:实验组大鼠海马GAD65 mRNA及其蛋白的表达随时间呈逐渐增高趋势,致痫后48小时～30天,GAD65 mRNA及其蛋白表达较对照组增高(48小时P<0.05;7～30天P<0.01);海人酸致痫后6小时、24小时实验组大鼠海马的GAD67mRNA及其蛋白表达较对照组增高(分别为P<0.01、P<0.05)。结论:颞叶癫痫急性期海马GAD67表达的增高及慢性期海马GAD65表达的增高是癫痫发生后机体的内源性抗痫机制。

The role of GAD65,GAD67 in self-acceleration mechanisms in the hippocampus of temporal lobe epilepsy rat

Objective: To discuss the affect of GAD65, GAD67 on endogenous self - acceleration mechanism in hippocampus after seizures. Methods: Epileptic rats were injected with kainate intraperitoneally to establish temporal lobe epilepsy model, the controls were injected with saline instead of kainate. At 3h, 6h, 12h, 24h, 48hours and 7d, 30 days after kainate injection, two group rats were anaesthetized and perfused, EEG were recorded antemortem By use of in situ hybridization, the GAD65 and GAD67 mRNA were analyzed at different time quantitatively in the dentate gyrus, CA1, CA3 regions of hippocampus, GAD65, GAD67 protein in the various subfields of hippocampus were detected by immuno-histochemistry at thesame time points as set in situ hybridization. Results: after kainate injected 48h, 7d,30d, the increase of GAD65 expression was significant, especially in 7-30 daysjGAD67 expression was dramatically increased in hippocampus at 6h following theonset of SE, at 24h, another increasing occurred. Conclusion: The up-regulation ofGAD67 in acute stage and GAD65 in chronical stage in hippocampus in temporallobe epilepsy might be the self-acceleration mechanism after seizures.