小胶质细胞活化对癫痫发病的影响

Effect of microglia activation on seizure

目的探讨抑制小胶质细胞活化对癫痫发作的影响及对脑神经元的保护作用。方法将大鼠随机分为4组:生理盐水对照组(NS组),海人酸致痫组(KA组),美满霉素预处理+海人酸组(MC+KA组),单纯美满霉素组(MC组)。采用免疫组化法观察各组大鼠造模后脑内OX-42、c-fos和caspase-3免疫反应性。RT-PCR或Western blot法检测造模后Apaf-1mRNA含量和caspase-3蛋白表达量。结果在KA致痫后2h大脑皮质及海马部位有明显的小胶质细胞活化、增殖,同时c-fos蛋白的表达在致痫组也较对照组显著增强,MC干预致痫组可明显减弱上述效应。Apaf-1mRNA的含量及caspase-3蛋白含量和免疫反应在造模后24h时间点四组之间无明显差异,在48h和72h时间点,KA组明显高于对照组(P<0.05),MC预处理则明显拮抗其高表达(P<0.05)。结论 KA致痫不仅通过提高神经元的兴奋性而且也通过激活小胶质细胞共同导致癫痫发作,二者相互协同作用,可进一步促进神经元凋亡,而MC能通过抑制小胶质细胞活化在癫痫中发挥神经保护作用。

Objective To investigate the effect of the inhibition of microglia activation on seizure and the protective effect of minocycline on cerebral neurons. Methods The rats were randomly divided into 4 groups：normal saline control（NS） ,kainic acid（KA）,minocycline pretreatment plus kainic acid（MC＋KA） and minocycline（MC）. The immunoreactivity of 0X-42, C-fos and caspase-3 in brain was detected by immu- nohistochemistry after modeling. The levels of ApaLi mRNA and caspase-3 protein were detected by RT- PCR and Western blot. Results The microglia was abviously activated and proliferated in cerabral cortex and hippocampus after the KA-induced seizure. The expression of c-los in KA was significantly higher than that of NS,while the pretreatment of minocycline obviously weakened this effect. Apaf-1 mRNA lev- els, caspase-3 protein levels and immunoreactivity showed no significant difference among 4 groups at 24h, while those of KA was abviously higher than those of NS at 48h and 72h （P〈O. 05） ,and minocycline pre- treatment significantly antagonized their expression （P〈O. 05）. Conclusion KA lead to seizure through activating microglia as well as increasing the excitability of neurons, they worked coordinately to increase the apoptosis of neurons, while minocycline can play a neural protective effect by inhibiting the activation of microulia.