拉喹莫德对中枢神经系统脱髓鞘小鼠胼胝体区少突胶质细胞的保护作用

摘要

目的 探讨拉喹莫德(LAQ)对双环己酮草酰二腙(CPZ)诱导的C57BL/6脱髓鞘小鼠胼胝体区少突胶质细胞的保护作用.方法 将80只C57BL/6雄性小鼠随机分为对照组(20只)、CPZ组(40只)、LAQ处理组(20只).免疫荧光法观察CPZ组不同时间点(0 d、3 d、7 d、2周、4周、8周)胼胝体区髓鞘碱性蛋白(MBP)和胶质纤维酸性蛋白(GFAP)阳性细胞的分布,免疫印迹法检测三组各个时间点MBP和GFAP蛋白水平,ELISA法检测TNF-α和IL-1β含量.结果 对照组各个时间点均未见脱髓鞘表现.与对照组相比,CPZ组MBP阳性细胞分布逐渐减少,然而GFAP阳性细胞分布逐渐增多,8周形成胶质瘢痕.与CPZ组比较,LAQ组于4周、8周时MBP蛋白表达均显著增加(均P<0.05),于7 d、2周、4周、8周时GFAP蛋白均显著降低(均P<0.05).与正常组相比,LAQ组和CPZ组于7 d、2周、4周、8周时TNF-α、IL-1β均显著升高(均P<0.05).与CPZ组相比,LAQ组于2周、4周、8周时TNF-α、IL-1β表达均显著减低(均P<0.05).结论 LAQ具有保护CPZ诱导的脱髓鞘小鼠胼胝体区少突胶质细胞的作用,可能与抑制活化的星形胶质细胞分泌的炎症因子有关.%Objective To explore the protective effects of laquinimod ( LAQ) on the oligodendrocytes at corpus callosum in C57BL/6 mice with cuprizone ( CPZ)-induced demyelination .Methods Eighty C57BL/6 male mice were randomly divided into control group (n=20), CPZ model group (n=40) and LAQ treatment group (n=20). Immunofluorescence staining was used to observe the distribution of myelin basic protein ( MBP) and glial fibrillary acidic protein (GFAP) positive cells at a series of time points (0 d, 3 d, 7 d, 2 weeks, 4 weeks, 8 weeks) in corpus callosum , the protein expressions of the MBP and GFAP in the three groups were measured by Western blot at a series of time points , the contents of TNF-αand IL-1βwere investigated by ELISA .Results The loss of myelin sheath were not detected by Western blot at each time point in the control group .Compare with the control group , MBP-positive cells in CPZ group showed sparse distribution gradually .However , the distribution of GFAP-positive cells in LAQ group increased gradually and there appeared to be glial scar at 8 weeks.Compared with CPZ group , the protein expression of MBP was significantly increased in LAQ group at 4, 8 weeks(all P<0.05), but the protein expression of GFAP was significantly decreased at 7 d, 2, 4 and 8 weeks (all P<0.05).Compare with the control group, the contents of TNF-αand IL-1βwere significantly increased in CPZ and LAQ groups at 7 d,2, 4 and 8 weeks ( all P<0.05 ) .Compare with the CPZ group , the contents of TNF-αand IL-1βwere decreased in LAQ group significantly at 2, 4 and 8 weeks(all P<0.05).Conclusion Laquinimod can protect the oligodendrocytes in the corpus callosum of cuprizone-treated demyelination mice , perhaps due to inhibition of the expression of inflammatory cytokines which were secreted by astrocyte activation .