Thalidomide Accelerates the Degradation of Extracellular Matrix in Rat Hepatic Cirrhosis via Down-Regulation of Transforming Growth Factor-beta1

ABSTRACT

PURPOSE: The degradation of the extracellular matrix has been shown to play an important role in the treatment of hepatic cirrhosis. In this study, the effect of thalidomide on the degradation of extracellular matrix was evaluated in a rat model of hepatic cirrhosis. MATERIALS AND METHODS: Cirrhosis was induced in Wistar rats by intraperitoneal injection of carbon tetrachloride (CCl4) three times weekly for 8 weeks. Then CCl4 was discontinued and thalidomide (100 mg/kg) or its vehicle was administered daily by gavage for 6 weeks. Serum hyaluronic acid, laminin, procollagen type III, and collagen type IV were examined by using a radioimmunoassay. Matrix metalloproteinase-13 (MMP-13), tissue inhibitor of metalloproteinase-1 (TIMP-1), and alpha-smooth muscle actin (alpha-SMA) protein in the liver, transforming growth factor beta1 (TGF-beta1) protein in cytoplasm by using immunohistochemistry and Western blot analysis, and MMP-13, TIMP-1, and TGF-beta1 mRNA levels in the liver were studied using reverse transcriptase polymerase chain reaction. RESULTS: Liver histopathology was significantly better in rats given thalidomide than in the untreated model group. The levels of TIMP-1 and TGF-beta1 mRNA and protein expressions were decreased significantly and MMP-13 mRNA and protein in the liver were significantly elevated in the thalidomide-treated group. CONCLUSION: Thalidomide may exert its effects on the regulation of MMP-13 and TIMP-1 via inhibition of the TGF-beta1 signaling pathway, which enhances the degradation of extracellular matrix and accelerates the regression of hepatic cirrhosis in rats.