Inhibitory effects of the herbal medicine Sho-saiko-to (TJ-9) on cell proliferation and procollagen gene expressions in cultured rat hepatic stellate cells

Background/Aims: It is of extreme importance to prevent liver fibrosis and subsequent progression to liver cirrhosis. The aim of our study was to elucidate in vitro whether Sho-saiko-to exerted inhibitory effects on hepatic stellate cells. Methods: Hepatic stellate cells were isolated from male Wistar rats. Water-soluble ingredients of Sho-saiko-to were obtained at concentrations of 10, 100, 250, 500 and 1000 μg/ml. Morphological transformation was observed under a phase-contrast microscope. Flow cytometric analysis was performed on day 4 after culture to evaluate the potential to proliferate of the stellate cells by analyzing cell cycles. Northern blot analysis was carried out on day 3 after culture to determine the expressions of type I and type III procollagen mRNAs. Results: (i) Sho-saiko-to 500 and 1000 μg/ml inhibited morphological transformation of the stellate cells to myofibroblast-like cells. (ii) Sho-saiko-to 500 and 1000 μg/ml significantly (p<0.0001) accumulated the cells in the G0/G1 phase (118.8±0.7%, 119.2±0.5%, respectively as compared with control) and significantly (p<0.0001) decreased cell numbers subsequently in G2/M phase (47.5±8.1%, 48.9±12.0%, respectively). (iii) Sho-saiko-to 500 and 1000 μg/ml also significantly (p<0.05 or p<0.0001) suppressed procollagen mRNA expression of type I to 51.5±6.4%, 34.9±3.7%, respectively, and type III to 51.3±12.3%, 46.7±11.4%, respectively. Conclusions: We have clarified the inhibitory effects of Sho-saiko-to on hepatic stellate cells in vitro. Shosaiko-to could be a potent inhibitor in the pathologenesis of liver fibrosis.