Genipin suppresses subconjunctival fibroblast migration, proliferation and myofibroblast transdifferentiation

Purpose: Inchin-ko-to is a herbal medicine which has therapeutic effects in ameliorating liver fibrosis or cholestatic liver diseases. Its main bioactive component is genipin, which is an intestinal bacterial metabolite of this medication. Accordingly, we determined whether or not Inchin-ko-to suppresses in a wound healing model subconjunctival fibroblast (SCF) migration proliferation and myofibroblast transdifferentiation since an inhibitory effect could be of value in improving trabeculotomy outcome. Methods: Effects of genipin on SCF cell migration were examined subsequent to wounding confluent monolayer cultures. Alamar blue staining evaluated the effects of genipin (0-50 mu g/ml) on fibroblast cell proliferation. Immunostaining determined alpha-smooth muscle actin (alpha SMA) expression. Western blotting evaluated (alpha SMA) expression and phospho-Smad2 formation. Real-time RT-PCR evaluated TGF beta 1 and collagen I alpha 2 mRNA expression. Enzyme-immunoassay determined culture medium collagen I content. Results: Genipin suppressed wound-induced cell migration and proliferation. It also decreased collagen type I TGF beta 1 and alpha SMA mRNA and protein expression. Smad2 signaling was inhibited by genipin in a dose-dependent manner. Conclusion: Genipin suppresses injury-induced fibrogenic responses in SCFs. This result suggests that the herbal medicine Inchin-ko-to might have therapeutic value following trabeculotomy. Copyright (c) 2006 S. Karger AG, Basel.