The role of basic fibroblast growth factor in oral submucous fibrosis pathogenesis

BACKGROUND: Oral submucous fibrosis (OSF) is a chronic fibrotic disease of oral mucosa and oropharynx, induced by betel quid chewing often resulting in restricted mouth opening. The principal cells implicated as a source of extracellular matrix in areas of fibrosis are fibroblasts. Accumulation of connective tissue matrix is secondary to factors such as cytokines and growth factors. The contribution of basic fibroblast growth factor (bFGF) in disease progression and the consequent stromal changes with increase in the severity of OSF was studied. METHODS: A case series analysis of 30 cases of OSF was carried out for bFGF expression using immunohistochemistry. Connective tissue changes in these cases were corroborated using aldehyde fuchsin and Verhoeff's hematoxylin special stains. RESULTS: bFGF immunoreactivity was found to be increased in fibroblasts and in endothelial cells in early OSF cases, while the expression of bFGF in stroma increased notably in advanced fibrosis. CONCLUSION: Increased bFGF expression in early stages of the disease was explainable to an initial injury phase because of areca consumption, followed by cellular activation by chemotactic cytokines and other growth factors with eventual fibrosis occurring as a result of molecular alteration at the cellular level.