难治性癫痫模型大鼠脑组织中srGAP2分子的表达★

摘要

背景：众多研究结果显示 srGAP2分子在突起生长和突触可塑性起到关键的作用，但具体机制不明。目的：检测 srGAP2在致痫大鼠模型中的表达，探讨 srGAP2与难治性癫痫发病机制的相关性。方法：选取雄性 SD 大鼠56只随机分为7组，其中随机选取6组建立癫痫模型，构成实验组，剩余1组作为对照组。分别选取癫痫发作后的6 h、1 d、1周、2周、1个月、2个月等6个时间点的颞叶脑组织作为研究对象，并与对照组进行比较。利用免疫组织化学、免疫荧光以及免疫印迹3种方法检测srGAP2在致痫动物模型以及对照组的脑组织中的表达及变化规律。结果与结论：实验组中 srGAP2除在皮质区表达增高外，还在海马区高表达，与对照组相比各时间点srGAP2在颞叶癫痫动物组中的表达含量逐渐升高，且在2周左右达高峰并维持，到2个月左右降至接近对照组水平。结果提示 srGAP2可能通过促进苔藓纤维出芽，进而导致脑组织中异常神经网络的建立，并最终在难治性癫痫的发生发展中起到重要作用。%BACKGROUND: Many studies show srGAP2 molecules play a key role in neurite outgrowth and synaptic plasticity, but the exact mechanism is unknown. OBJECTIVE: To study the possible correlation between srGAP2 expression and epilepsy pathogenesis, through testing the expression of srGAP2 in epileptic rats. METHODS: Fifty-six Sprague-Dawley male rats were divided randomly into seven groups, including six groups with epilepsy induced by lithium-pilocarpine management and one control group. The samples of temporal lobe tissue were taken from rats at 6 hours, 1 day, 1 week, 2 weeks, 1 month, and 2 months after seizures, and from controls group. Using immunohistochemistry, immunefluorescence, and western-blot methods, we tested the expression of srGAP2 in experimental animals and control groups. RESULTS AND CONCLUSION: Western blotting of rat brain tissue showed that srGAP2 was up-regulated in the cortex and hippocampus of the epileptic rats as compared with the control rats. The maximal expression was seen at about 2 weeks, and relatively high expression maintained until 1 month. The expression then returned down, and approached normal levels at 2 months. These results were consistent with the immunohistochemical and immunofluorescence results. These data implicate srGAP2 may promote mossy fiber sprouting, and participate in the abnormal development of synapses. The result suggests that this protein may play an important role in the pathogenesis of intractable epilepsy.