IL-1β对脓毒症新生幼鼠胼胝体内少突胶质细胞前体细胞分化成熟的影响

摘要

[ ABSTRACT] AIM:To explore whether IL-1βinhibits the oligodendrocyte precursor cell ( OPCs) differentiation and affects axonal myelination.METHODS:One-day-old SD rats were randomly divided into control group and LPS group ( 48 rats in each group) .The rats in LPS group were intraperitoneally injected with 1 mg/kg LPS.The rats in control group were injected with an equal volume of PBS.The rats in each group were further divided into 3 h, 24 h, 3 d, 7 d, 14 d and 28 d subgroups after injection.The expression of IL-1βand IL-1R1 in the rat corpus callosum at 3 h, 24 h, 3 d, 7 d was determined by double immunofluorescence and Western blotting.The myelin basic protein( MBP) expression in the rat cor-pus callosum at 14 d, 28 d after injection was also measured.In vitro, primary OPCs culture was performed and divided in-to control group, 30 μg/L IL-1βgroup, 30 μg/L IL-1β+IL-1Ra group and 30 μg/L IL-1Ra group.The expression of MBP in the OPCs induced differentiation for 3 d was observed by double immunofluorescence and Western blotting.RE-SULTS:The expression of IL-1βand IL-1R1 in the rat corpus callosum at 3 h, 24 h, 3 d, 7 d after LPS injection was ob-viously increased and the expression of MBP in the rat corpus callosum at 14 d, 28 d in LPS group was obviously decreased compared with control group in vivo.The level of MBP was significantly decreased after IL-1βtreatment for 3 d in vitro. However, IL-1Ra (IL-1R inhibitor) reversed the down-regulation of MBP expression.IL-1βinhibited the expression of p-ERK, ERK over-expression reversed the down-regulation of MBP expression compared with IL-1βgroup.CONCLUSION:IL-1βinhibits the differentiation of OPCs, which may be involved in ERK pathways, thus leading to axonal hypomyelination in the corpus callosum of septic neonatal rats.%目的：探讨IL-1β对少突胶质细胞前体细胞（OPCs）分化成熟及轴突髓鞘化的影响。方法：将出生1 d的SD幼鼠96只随机分为2组：对照组和脂多糖（ LPS）组各48只。 LPS组给予腹腔注射1mg／kg LPS，对照组腹腔注射等体积PBS。根据注射后时间分为3 h、24 h、3 d、7 d、14 d、28 d 6个亚组，应用双标免疫组化及Western blotting的方法观察3 h、24 h、3 d、7 d时IL-1β及IL-1受体1（IL-1R1）的表达和14 d、28 d时髓鞘碱性蛋白（MBP）的表达。进行原代OPCs培养将其分为对照组、IL-1β组、IL-1β＋IL-1受体拮抗剂（ IL-1Ra）组及IL-1Ra组。将其诱导分化3 d后利用免疫荧光及Western blotting比较4组间MBP的表达。结果：与对照组相比，LPS注射后3 h、24 h、3 d、7 d幼鼠胼胝体小胶质细胞表达IL-1β明显增加，其受体在OPCs表达增加。 LPS注射后14 d、28 d，MBP在胼胝体的表达下降。细胞实验显示原代OPCs培养诱导分化3 d后IL-1β可以抑制MBP的表达，并且可以被IL-1Ra逆转。 IL-1β可抑制磷酸化ERK的表达，ERK过表达可逆转IL-1β对MBP的抑制作用。结论：在脓毒症新生幼鼠胼胝体内IL-1β有可能通过抑制ERK通路来抑制OPCs成熟，从而导致脑白质轴突低髓鞘化。