Fasudil hydrochloride hydrate, a Rho-kinase (ROCK) inhibitor, suppresses collagen production and enhances collagenase activity in hepatic stellate cells

: Background/Aims: The Rho–ROCK signaling pathways play an important role in the activation of hepatic stellate cells (HSCs). We investigated the effects of fasudil hydrochloride hydrate (fasudil), a Rho‐kinase (ROCK) inhibitor, on cell growth, collagen production, and collagenase activity in HSCs. Methods: Rat HSCs and human HSC‐derived TWNT‐4 cells were cultured for studies on stress fiber formation and α‐smooth muscle actin (α‐SMA) expression. Proliferation was measured by BrdU incorporation, and apoptosis by TUNEL assay. The phosphorylation states of the MAP kinases (MAPKs), extra cellular signal –regulated kinase 1/2 (ERK1/2), c‐jun kinase (JNK), and p38 were evaluated by western blot analysis. Type I collagen, matrix metalloproteinase‐1 (MMP‐1) and tissue inhibitor of matrix metalloproteinase‐1 (TIMP‐1) production and gene expression were evaluated by ELISA and real‐time PCR, respectively. Collagenase activity (active MMP‐1) was also evaluated. Results: Fasudil (100 μM) inhibited cell spreading, the formation of stress fibers, and expression of α‐SMA with concomitant suppression of cell growth, although it did not induce apoptosis. Fasudil inhibited phosphorylation of ERK1/2, JNK, and p38. Treatment with fasudil suppressed the production and transcription of collagen and TIMP, stimulated the production and transcription of MMP‐1, and enhanced collagenase activity. Conclusion: These findings demonstrated that fasudil not only suppresses proliferation and collagen production but also increases collagenase activity.