缺氧缺血致脑室周围白质软化新生大鼠连接蛋白47表达及其对少突胶质细胞髓鞘化的影响  

Expression of connexin 47 and its effects on the myelination of oligodendrocytes in hypoxia-ischemia-induced periventricular leukomalacia in newborn rats

作　　者：侯阿娜[1] 曲双双 富建华[1] HOU Ana;QU Shuangshuang;FU Jianhua(Department of Pediatrics,Shengjing Hospital,China Medical University,Shenyang 110004,China;Department of Pediatrics,General Hospital of Northern Theater Command,Shenyang 110016,China)

机构地区：[1]中国医科大学附属盛京医院儿科,沈阳110004 [2]北部战区总医院儿科,沈阳110016

出　　处：《中国医科大学学报》2020年第4期306-312,共7页Journal of China Medical University

基　　金：国家自然科学基金(81601331)。

摘　　要：目的探讨连接蛋白(Cx)47在缺氧缺血(HI)致新生大鼠脑室周围白质软化(PVL)发生、发展中表达,阐明Cx47对少突胶质细胞(OLs)髓鞘化的影响。方法将120只出生3 d的新生大鼠随机分为HI组和对照组,每组各60只。采用右侧颈总动脉结扎后低氧2 h建立PVL动物模型,在手术后l、3、7、14 d分别留取脑组织标本,采用HE染色、透射电镜观察脑组织形态学改变,免疫组化、Western blotting和实时PCR方法检测2组Cx47蛋白和基因表达。结果光镜下可见对照组脑组织结构致密,神经胶质细胞形态完整,排列均匀,胞核大,染色清晰。HI组手术后1 d细胞间隙增宽,细胞肿胀、变形、细胞核固缩;手术后3 d可见侧脑室旁白质细胞大量坏死,神经纤维走行紊乱,脑组织结构疏松模糊呈囊性及筛网状坏死;手术后7 d脑室旁白质坏死区域更为广泛,呈簇状及点状坏死,水肿减轻,出现不同程度胶质增生;手术后14 d脑白质胼胝体变薄,纤维走向紊乱,呈网状或条索状,部分出现囊腔病变侧脑室扩大。透射电镜下对照组呈现完整的细胞形态,细胞间缝隙连接紧密;HI组可见OLs出现溶解碎裂,细胞之间缝隙连接开放。免疫组化可见Cx47与髓鞘碱性蛋白(MBP)表达定位于OLs,与对照组比较,HI组Cx47与MBP表达均减少(P<0.01)。2组Cx47蛋白及基因表达水平随大鼠日龄增加而增加;与对照组比较,HI组各时间Cx47表达均较降低(P<0.01)。结论在HI致PVL新生大鼠模型中存在OLs损伤、髓鞘化障碍、缝隙连接开放,在此过程中Cx47表达显著降低,提示Cx47可能参与髓鞘化障碍及缝隙连接开放。Objective This study aimed to investigate the expression of the gap junction protein,connexin(Cx)47 and its effects on the development of hypoxia-ischemia(HI)-induced periventricular leukomalacia(PVL),particularly on the myelination of oligodendrocytes(OLs).Methods A total of 120 rats were randomly divided into HI or control groups(n=60 per group).Morphological changes in brain tissue were observed under a light microscope and a transmission electron microscope.The expression levels of Cx47 were determined by immunohistochemical staining,Western blotting,and real-time PCR.Results When observed under a light microscope,the structure of the brain was found to be compact,the glial cells were morphologically complete and uniformly arranged,and nuclei were clearly stained in the control group.However,in the HI group,necrosis of white matter tissues,a disorderly arrangement of nerve fibers,loose and fuzzy brain tissue structure,and atrophy of the corpus callosum were observed.Under the transmission electron microscope,the HI group showed dissolved,fragmented OLs and opened gap junctions.Using immunohistochemical staining,Cx47 and myelin basic protein were found to be expressed in OLs and their expression levels decreased in the HI group compared with the control group(P<0.01).The protein and mRNA expression levels of Cx47 were significantly lower in the HI group than the control group at each time point(P<0.01).Conclusion OLs impairments,obstruction of myelination,and the opening of gap junctions were observed in an HI-induced newborn rat model of PVL.Meanwhile,there was a concurrent decrease in Cx47 expression,indicating the possibility that Cx47 is involved in the obstruction of myelination and the opening of gap junctions in PVL.

关 键 词：连接蛋白47 少突胶质细胞 髓鞘化 缝隙连接 脑室周围白质软化 

分 类 号：R722.6[医药卫生—儿科]