Study on Nogo-B participating in transforming growth factor-β1/Smad2 signaling pathway in mice models of hepatic fibrosis / 中华传染病杂志

ABSTRACT

Objective 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 pointssubgroups 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.