Rimonabant inhibits proliferation, collagen secretion and induces apoptosis in hepatic stellate cells.

Background/aims: Liver fibrosis represents a significant health problem worldwide. Hepatic stellate cells (HSCs) play a critical role in the live fibrosis. Rimonabant (SR141716) is cannabinoid receptor type 1 (CB1) antagonist. The pharmacological effects of rimonabant on HSCs are not well characterized in HSCs.

Methods: CB1 receptor was detected by immunohistochemistry in human liver fibrosis specimens. Cell proliferation was detected by MTT assay. Cell apoptosis, caspase-3 protein expression and cell cycle were detected by TEM and flow cytometry, respectively. Caspase-3 activity was measured using caspase-3 activity assay kit. Collagen secretion was evaluated by radioimmunoassay. CB1 receptor and signaling molecules were evaluated by qRTPCR and Western blot.

Results: Immunohistochemistry showed a discrete, punctuated CB1 immunoreactivity in human liver fibrosis specimens. Rimonabant reduced HSC proliferation and increased HSC apoptosis. Cell cycle analysis showed a decrease in G2/M phase cells and an increase in G0/G1 phase cells in HSC-T6 cells treated with rimonabant. Caspase-3 protein expression and activity were increased by rimonabant. Rimonabant decreased collagen secretion in HSC-T6 cells. Moreover, rimonabant inhibited the expression of phosphorylated FAK and ERK and down-regulated CB1 mRNA expression.

Conclusion: The study provides new insights toward the pharmacological effect of rimonabant on HSCs in vitro. Rimonabant inhibits proliferation, collagen secretion and induces apoptosis in HSCs.