溴化乙锭诱导的脱髓鞘模型大鼠胼胝体内MCT1表达的形态学观察

Morphological observation of MCT1 expression in corpus callosum in demyelinating model of rats by ethidium bromide

目的:观察单羧酸转运体-1(monocarboxylate transporter-1,MCT1)在溴化乙锭(Ethidium Bromide,EB)诱导的脱髓鞘模型大鼠胼胝体(corpus callosum,CC)内的表达变化。方法:选用正常成年SD大鼠,随机分为正常组、溶剂组和EB组,将0.05%的EB注射到大鼠胼胝体制作脱髓鞘模型,Luxol Fast Blue(LFB)染色观察胼胝体中的髓鞘是否脱失,免疫荧光组织化学染色技术检测注射位点MCT1的表达情况。结果:与正常组相比,注射EB14 d后注射部位胼胝体的LFB染色极浅且不均匀;通过MCT1分别与环核苷酸磷酸二酯酶(cyclic nucleotide phosphodiesterase,CNPase)和GFAP免疫荧光双标可以看出,在正常大鼠胼胝体中,大部分表达MCT1的细胞为CNPase+的少突胶质细胞(oligodendrocytes,OLs),少部分表达MCT1的细胞是GFAP+细胞;注射EB14 d后,EB注射部位胼胝体中CNPase的表达明显减弱,且CNPase+细胞中MCT1的表达也减弱,而GFAP的表达则增强,且所有GFAP+细胞都表达MCT1。结论:在正常SD大鼠胼胝体中,MCT1主要在少突胶质细胞中表达,EB诱导胼胝体脱髓鞘后,MCT1主要在星形胶质细胞中表达。

ObjectiVe： To observe the expression change of monocarboxylate transporter-1 （MCT1） in corpus callosum （CC） in demyelinating model rats by etbidium bromide （EB）. Methods： Adult SD rats were randomly divided into 3 groups： control group, vehicle group and EB group. The demyelinating model was established using stereotactic injection of EB solution （0, 05 % ） into the corpus callosum of rats. Luxol Fast Blue （LFB） staining was used to examine the extent of demyelination in corpus caUosum, and the expression of MCT1 in the EB lesion of corpus callosum was obesrved by im- munofluoreseence staining. Results： At 14 days after EB injected, poor LFB staining was observed in the corpus callosum of injection side compared to the control group. In the normal rats corpus callosum the majority of MCT1 ＋ cells were co- labeled with CNPase ＋ （ cyclic nucleotide phosphodiesterase） oligodendrocytes （OLs） and the minority of MCT1 ＋ cells were co-labeled with GFAP ＋ astrocytes. The density of CNPase immunofluorescence staining was significantly decreased in the corpus callosum of injection side. Meanwhile, the MCT1 expression in CNPase ＋ OLs also was attenuated. Con- versely, the expression of GFAP was enhanced, and almost all of GFAP ＋astrocytes were MCT1 ＋. Conclusion： MCT1 is dominantly expressed in OLs in the corpus callosum in normal SD rats, while it is mainly expressed in astrocytes in the corpus callosum following the EB induced demyelination.