Fungus thielavia minor blocks hepatic stellate cell proliferation and inhibits experemental hepatic fibrosis in rats

Abstract

Introdnction and Aim: Hepatic stellate cells (HSCs) are proliferated by cytokines such as PDGF and produce extracellular matrix (ECM) in response to TGF[3 1 in hepatic fibrosis. On the other hand, Fungus thielavia minor (OPC15161) inhibits mesangial cell proliferation and ECM production by the ceils, which are the principal cells producing ECM in the kidney. In this study, we examined the inhibitory effects of OPC-15161 against the HSC proliferation and ECM production in vitro, and against the rat thioacetamide (TAA)-induced hepatic fibrosis in vivo. Methods: In vitro: HSCs were isolated from Wistar rats by the collagenase perfusion method using an elutriation rotor and cultured for 24 hours. To determine the inhibitory effect of OPC-15161 on proliferation and ECM production, the uptake of 3H-thymidine and the production of 3H-hydroxyproline were compared in the presence of PDGF (10ng/ml) and TGFI~ 1 (lng/ml) and various concentrations (0-30 la g/ml) of OPC-15161. The changes of inocitol-triphosphate ( IP3) concentration and Ca 2÷ mobilization in HSCs with OPC-15161 were examined with an IP.~-assay system kit and by confocal scanning laser microscopy using Fluo-3AM, respectively. In vivo: TAA (200mg/kg) was injected intrapertioneally into rats for 12 weeks. Animals were given a diet containing OPC-15161 (group I) or standard diet (group I1) from 9 to 12 weeks. The degree of hepatic fibrosis, the mRNA expression by Northern blotting and the immunolocalization of type I procollagen were evaluated between group I and group II. In addition, the detection of HSCs in liver tissues of groups I and II was performed by immunohistochemistry (ABC methods) using anti-desmin antibody as a primary antibody. Results and Conclusion: 3H-thymidine uptake and the amount of 3H-hydroxyproline in cultured HSCs were significantly increased by PDGF and TGF13 1, but decreased dose-dependently by OPC-15161. The intracellular IP 3 and Ca 2÷ levels were increased by PDGF, but were suppressed by OPC-15161. In the rat TAA hepatic fibrosis model, the deposition of ECM and the expression of type I procollagen and desmin in the liver were significantly suppressed by OPC-15161. These results indicate that OPC-15161 blocks HSC proliferation through the IP3-Ca2* system and inhibits the process of the hepatic fibrosis in rats.