RESUMO
OBJECTIVE: The aim of this study was to induce a rat model of oral submucous fibrosis (OSF) using bleomycin. STUDY DESIGN: A randomized trial was performed. Bleomycin dilution or phosphate-buffered saline was injected daily into the buccal mucosa of the test and control rats, respectively, for 2, 4, 6, or 8 weeks. Changes in histopathologic features, myofibroblasts, ultrastructure, and the levels of collagen type I and III, transforming growth factor-beta 1, and interferon-γ were measured. RESULTS: Compared with controls, the buccal mucosa of the test rats appeared pale and stiff. There was collagen deposition in the laminae propria. Type I and type III collagen increased steadily, transforming growth factor-beta 1 increased and then decreased, and interferon-γ was gradually reduced. The ultrastructure was also similar to that of OSF. CONCLUSIONS: Using bleomycin, we induced a rat model of OSF that is very similar to human OSF in clinical manifestations, pathology, and ultrastructural changes.
