大麻素对双环己酮草酰二腙诱导的脱髓鞘模型小鼠髓鞘的修复作用

Repair effect of cannabinoid on myelin sheath of demyelination model mice induced by cuprizone

目的:探讨大麻素(WIN55212-2)对双环己酮草酰二腙(cuprizone)诱导的脱髓鞘模型小鼠髓鞘的修复作用,阐明其可能机制。方法:选取C57BL/6小鼠95只,随机分为空白对照组、模型组(0.2%的cuprizone饲料喂养6周)、二甲基亚砜(DMSO)组(0.2%cuprizone饲料喂养3周后开始腹腔注射等量的DMSO混合液)和治疗组(0.2%cuprizone饲料喂养3周后开始腹腔注射1mg·kg-1 WIN55212-2)。采用黑金Ⅱ髓鞘染色技术对小鼠髓鞘组织染色,观察其组织形态表现;采用Western blotting法检测小鼠大脑组织中结侧蛋白(JN)、髓鞘碱性蛋白(MBP)和转录因子Nkx 2.2蛋白表达水平。结果:黑金Ⅱ髓鞘染色,空白对照组小鼠大脑胼胝体区域有明显的着色,模型组小鼠大脑胼胝体区着色较浅。与空白对照组比较,模型组小鼠大脑组织中JN和MBP蛋白表达水平均明显降低(P<0.05);与模型组和DMSO组比较,治疗组小鼠大脑组织中JN和Nkx2.2蛋白表达水平明显升高(P<0.05或P<0.01)。结论:大麻素可能通过转录因子Nkx2.2蛋白促进cuprizone诱导的脱髓鞘模型小鼠大脑组织中JN蛋白表达,促进髓鞘再生和修复。

Objective:To investigate the repair effect of cannabinoid(WIN55212-2)on the myelin sheath of the demyelination model mice induced by cuprizone,and to elucidate its possible mechanism.Methods:A total of 95 C57BL/6 mice were randomly divided into blank control group,model group(0.2% cuprizone for 6 weeks),DMSO group(intraperitoneally injected with the same amount of DMSO mixture from the 3 rd week of feeding 0.2% cuprizone)and treatment group(intraperitoneally injected with 1 mg·kg-1 WIN55212-2 from the 3 rd week of feeding 0.2% cuprizone).The myelin sheath tissue of the mice was stained by Black-goldⅡstaining technique,and its histomorphology was observed.The expression levels of juxtanodin(JN),myelin basic protein(MBP)and Nkx2.2 proteins in mouse brain tissue were detected by Western blotting method.Results:The results of Black-goldⅡstaining showed that the corpus callosum of the brain of the mice in blank control group had significant coloration,while the corpus callosum of the mice in model group showed less coloration.Compared with blank control group,the expression levels of JN and MBP proteins in brain tissue of the mice in model group were significantly decreased(P<0.05).Compared with model group and DMSO group,the expression level of JN and Nkx2.2 proteins in brain tissue of the mice in treatment group were significantly increased(P < 0.05 or P < 0.01).Conclusion:Cannabinoid may promote the JN expression in brain tissue of the cuprizone-induced demyelinating model mice through the transcription factor Nkx2.2,and further promote the remyelination and repair.