摘要目的 探讨在小鼠肝纤维化模型中Nogo-B与转化生长因子-β1(TGF-β1)/Smad2信号通路的关系.方法 将24只健康雄性ICR小鼠分为正常对照组6只和肝纤维化模型组18只,模型组再按造模后不同时间点分为4、8和12周3个亚组.肝纤维化模型组皮下注射四氯化碳(CCl4)诱导小鼠肝纤维化模型,肝组织经HE和Masson染色后,光学显微镜下观察各组肝组织病理变化；RT-PCR方法检测各组肝脏Nogo-B、Smad2和TGF-β1 mRNA表达；Western印迹法、免疫组织化学法检测各组肝脏Nogo-B、Smad2、TGF-β1蛋白表达.组间均数比较采用单因素方差分析.结果 CCl4成功诱导肝纤维化模型.Nogo-B两种亚型Nogo-B1、Nogo-B2 mRNA在正常肝组织表达为0.140±0.050和0.104±0.023,在肝纤维化模型组肝脏中表达显著增加,造模12周时为1.054±0.040和0.500±0.057(F=431.41、135.46,均P＜0.01)；Nogo-B蛋白主要表达于肝脏间质中,肝细胞仅少量表达；且Nogo-B mRNA及蛋白的表达强度与参与肝纤维化信号通路相关因子Smad2、TGF-β1 mRNA及蛋白均呈正相关(均P＜0.01).结论 Nogo-B可能通过参与TGF-β1/Smad2信号通路在肝纤维化发展过程中起重要作用,促进肝纤维化的发展.

abstractsObjective To study the relationship between Nogo-B and transforming growth factor-β1 (TGF-β1)/Smad2 signaling pathway in mice models of hepatic fibrosis.Methods Twenty four healthy male ICR mice were divided into two groups,with 6 in the control group and 18 in the model group.Mice in the model group were further divided into three subgroups according to different time points:subgroups of 4,8 and 12 weeks,with 6 mice in each subgroup.Hepatic fibrosis of mice was induced by subcutaneous injection of carbon tetrachloride (CCl4).The histopathologic changes of the liver were observed by optical microscope using hematoxylin-eosin and Masson trichrome stainings of the liver tissues.Expressions of Nogo-B,Smad2 and TGF-β1 mRNA and proteins in liver were detected by reverse transcription-polymerase chain reaction (RT-PCR),Western blot and immunohistochemistry assays,respectively.Means among groups were compared by univariate analysis of variance.Results The hepatic fibrosis models were successfully induced by CCl4 injection.The expressions of two subtypes of Nogo-B,Nogo-B1 and Nogo-B2 mRNA in normal livers were 0.140±0.050 and 0.104±0.023,but both significantly increased in the livers of mice in the 12 week model subgroup (1.054±0.040 and 0.500±0.057,F=431.41 and 135.46,respectively; both P＜0.01).The Nogo-B protein was mainly expressed in nonparenchymal cells of the liver,and was hardly expressed in hepatocytes.Linear correlation analysis showed that the expressions of Nogo-B mRNA and proteins were positively correlated with Smad2 and TGF-β1 mRNA and proteins (all P＜0.01),which were considered to participate in the signaling pathway of hepatic fibrosis.Conclusion Nogo-B might play a role in the development and progression of hepatic fibrosis by participating in TGF-β1/Smad2 signaling pathway.