Regulation Mechanism Of TIMP-1 Expression By Active Herbal Constituents In Rat Hepatic Stellate Cells

Objective: we studied the effects of protein kinase C activator PMA and inhibitor Ro31-8220, apigenin and fisetin as well as active herbal ingredient emodin, on the regulation mechanism of TIMP-1 expression in an immortalized rat hepatic stellate cell line, HSCs-T6. Methods: TIMP-1 expression was detected by RT-PCR and Western-blot analysis. The TIMP-1 AP-1-binding sites reporter gene assays were also used to detect the effect of these drugs on AP-1 activites. Otherwise, we valued the effect of emodin on the binding activities of AP-1 by EMSA and on JunD mRNA expression by RT-PCR analysis. Results: Emodin, Apigenin and Fisetin inhibited both TGFβ1-induced and PMA-induced TIMP-1 expression. Reporter gene assays found that PKC inhibitors and herbal constituents reduced both basal and PMA-induced AP-1 promoter activities. Emodin reduced AP-1 DNA binding activities of HSC-T6 cells by EMSA, and also attenuated Jun D mRNA expression in HSC-T6 cells. Conclusion: Emodin, apigenin and fisetin may act as active antifibrotic agents through regulation of TIMP-1 expression; PKC may play an important role in the expression of TIMP-1 via transactivator AP-1.