Thrombin 誘導頰黏膜纖維母細胞 CTGF 表現機轉及以EGCG 治療口腔黏膜下纖維化症潛力之研究

Abstract

Thrombin has been implicated in fibrotic disorders of several organs such as kidney, liver, and lung. Connective tissue growth factor (CTGF) is associated with the onset and progression of fibrosis in many human tissues and was found to overexpress in oral submucous fibrosis (OSF). OSF is the result of persistent chemical irritation from areca nut (AN) constituents and the mechanical trauma to the oral mucosa from the coarse fibers of AN. Mechanical trauma could lead to activation of the coagulation cascade. In this study, we showed that thrombin stimulated CTGF synthesis in human buccal mucosal fibroblasts (BMFs). The effect of thrombin could be mimicked with a selective proteinase activated receptors 1 (PAR1)-activating peptide and was completely abolished with the specific thrombin serine protease inhibitor PPACK, indicating that thrombin mediated this effect via the proteolytic activation of PAR1. These results suggested that thrombin produced by microtrauma during AN chewing may contribute to the pathogenesis of OSF by up-regulating CTGF expression in BMFs. Pretreatment with antioxidant N-acetyl-L-cysteine, ASK1 inhibitor thioredoxin, JNK inhibitor SP600125, but not PI3K inhibitor LY294002, ERK inhibitor PD98059, p38 MAPK inhibitor SB203580, significantly reduced thrombin induced CTGF synthesis. Furthermore, epigallocatechin-3-gallate completely inhibited thrombin-induced CTGF synthesis. These results suggested that thrombin-induced CTGF synthesis could be mediated by reactive oxygen species, ASK1 and JNK pathways in BMFs and EGCG may serve as a useful agent in controlling OSF.