氯化锂-毛果芸香碱致大鼠海马髓鞘及少突胶质细胞系变化初步研究

A Preliminary Study of Hippocampal Myelin Sheath and Oligodendrocyte Lineage Changes in Rats with LiCl-pilocarpine Induced Chronic Epilepsy

目的研究氯化锂-毛果芸香碱致大鼠不同时期海马髓鞘损伤及少突胶质细胞系变化。方法健康成年雄性SD大鼠建立氯化锂-毛果芸香碱慢性癫模型,分为对照组、急性期组(致后24 h内)、潜伏期组(致后2周内)、慢性期组(致后2个月),各组(均n=4)。采用伊文思蓝法检测各组大鼠海马血脑屏障(BBB)通透性改变;免疫荧光染色法检测海马神经元数目、髓鞘碱性蛋白(MBP)表达水平、2',3'-环核苷酸3'-磷酸二酯酶(CNPase)阳性成熟少突胶质细胞数目、未成熟少突胶质细胞标记物(O4)表达水平、硫酸软骨素蛋白多糖(NG2)阳性少突胶质祖细胞数目。结果大鼠致后,急性期组、潜伏期组和慢性期组大鼠海马各区域BBB通透性均较对照组增加(P<0.05),以急性期组增加最为显著。各组大鼠海马不同区域NeuN阳性神经元数目均较对照组显著下降(P<0.05)。潜伏期组和慢性期组海马各区域MBP表达水平及CNPase阳性细胞数目均显著低于对照组(P<0.05);各组海马CA1、Hilus区O4表达水平及NG2阳性细胞数目均较对照组显著增加(P<0.05),以潜伏期组增加最为明显。结论氯化锂-毛果芸香碱致大鼠海马区BBB通透性增加,未成熟少突胶质细胞和少突胶质祖细胞免疫荧光表达上调,髓鞘及成熟少突胶质细胞存在一定程度损伤。

Aim To explore the hippocampal myelin sheath injuries and Ollgodendrocyte lineage changes of different phases in rats with LiCl-pilocarpine induced chronic epilepsy. Methods Healthy adult male SD rats were induced by LiCl and pilocarpine to establish chronic epilepsy model, and were divided into a control group, a acute phase group （within 24 hours after seizure）, a latent phase group （within 2 weeks after seizure）, a chronic phase group （2 months after seizure）. The changes of blood brain barrier permeability of different hippocampus areas were evaluated using Evans blue extravasation and fluorescence intensity measurement. Immunofluorescence staining was used to measure the number of neurons, myelin basic protein expression level, number ofCNPase＋ mature oligodendrocyte cells, 04 expression level, number of NG2＋ oligodendrocyte precursor cells in different hippocampus areas of different groups. Results The blood brain barrier permeability of hippocampus CA1/CA3/Hilus areas increased in all the epilepsy groups including acute/latent/ chronic phase groups compared with the control group （P〈0.05）, with the acute phase group as the highest. The number of NeuN＋ cells of different areas decreased in each epilepsy group, with respective significant difference compared with the control group （P〈0.05）. The myelin basic protein expression level and the number of CNPase＋ cells of latent and chronic phase group of each area were significantly lower than the control group （P〈0.05）. The 04 expression level and number of NG2＋ cells of CA1 and Hilus area in all the epilepsy groups significantly increased compared with the control group （P〈0.05）, with the latent phase group as the highest. Conclusion In rats with LiCl-pilocarpine induced chronic epilepsy, the BBB permeability of hippocampus increased, and the fluorescence expression of immature oligodendrocyte cells and oligodendrocyte precursor cells were both upregulated, and the myelin sheath of hippocampus and mature oligodendrocyte cells were injured to some extent.