Department of General Surgery, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, China.
Hepatobiliary Pancreat Dis Int. 2011 Feb;10(1):64-71. doi: 10.1016/s1499-3872(11)60009-x.
Hepatic fibrosis is a necessary step in the development of hepatic cirrhosis. In this study we used lentiviral vector-mediated transfection technology to evaluate the effect of peroxisome proliferator-activated receptor gamma (PPAR-gamma) on rat hepatic fibrosis.
Hepatic fibrosis in rats was induced by CCl4 for 2 weeks (early fibrosis) and 8 weeks (sustained fibrosis). The rats were randomly divided into four groups: normal control, fibrosis, blank vector, and PPAR-gamma. They were infected with the recombinant lentiviral expression vector carrying the rat PPAR-gamma gene by portal vein injection. The liver of the rats was examined histologically and hydroxyproline was assessed. In vitro primary hepatic stellate cells (HSCs) were infected with the recombinant lentiviral expression vector carrying the rat PPAR-gamma gene. The status of HSC proliferation was measured by the MTT assay. The protein levels of PPAR-gamma, alpha-smooth muscle actin (alpha-SMA) and type I collagen expression were evaluated by the Western blotting method.
In vitro studies revealed that expression of PPAR-gamma inhibited expression of alpha-SMA and type I collagen in activated HSCs (P<0.01) as well as HSC proliferation (P<0.01). In vivo experiments indicated that in the early hepatic fibrosis group, the hydroxyproline content and the level of collagen I protein in the liver in the PPAR-gamma transfected group were not significantly different compared to the hepatic fibrosis group and the blank vector group; whereas the expressions of PPAR-gamma and alpha-SMA were different compared to the hepatic fibrosis group (P<0.01). In the sustained hepatic fibrosis group, there were significant differences in the hydroxyproline content and the expression of PPAR-gamma, alpha-SMA, and type I collagen between each group.
PPAR-gamma can inhibit HSC proliferation and hepatic fibrosis, and suppress alpha-SMA and type I collagen expression.
肝纤维化是肝硬化发展的必要步骤。本研究采用慢病毒载体介导的转染技术，观察过氧化物酶体增殖物激活受体γ（PPAR-γ）对大鼠肝纤维化的影响。
采用 CCl4 诱导大鼠肝纤维化 2 周（早期纤维化）和 8 周（持续纤维化）。将大鼠随机分为 4 组：正常对照组、纤维化组、空白载体组和 PPAR-γ 组。通过门静脉注射感染携带大鼠 PPAR-γ 基因的重组慢病毒表达载体。肝组织学检查及羟脯氨酸测定。体外原代肝星状细胞（HSCs）感染携带大鼠 PPAR-γ 基因的重组慢病毒表达载体。MTT 法检测 HSC 增殖状态。Western blot 法检测 PPAR-γ、α-平滑肌肌动蛋白（α-SMA）和Ⅰ型胶原的蛋白表达水平。
体外研究表明，PPAR-γ 的表达抑制了激活的 HSCs 中 α-SMA 和Ⅰ型胶原的表达（P<0.01）以及 HSC 的增殖（P<0.01）。体内实验表明，在早期肝纤维化组，PPAR-γ 转染组肝组织羟脯氨酸含量和Ⅰ型胶原蛋白水平与肝纤维化组和空白载体组无显著差异；而与肝纤维化组相比，PPAR-γ 和 α-SMA 的表达不同（P<0.01）。在持续肝纤维化组，各组羟脯氨酸含量及 PPAR-γ、α-SMA 和Ⅰ型胶原的表达均有显著差异。
PPAR-γ 可抑制 HSC 增殖和肝纤维化，抑制 α-SMA 和Ⅰ型胶原的表达。
