Expression of fibrosis-related molecules in the oral mucosa of six animal species: A reference for selecting animal models.

Several animal models have been used in studies associated with oral submucous fibrosis (OSF); however, an appropriate model based on the histopathological characteristics of OSF is still needed. This study aimed to provide histological references for selecting a potential model. The expression intensities of collagen type I (Col I), type III (Col III), type IV (Col IV), fibronectin (FN), transforming growth factors β (TGF-β), and connective tissue growth factor (CCN2) in the oral mucosa of the human and six non-human animal species were measured by immunohistochemistry. There was little variation in the expression intensity of Col I while the expression of Col III, Col IV, and FN showed differences. The expression intensities of TGF-β in dog, rat, sheep, and pig oral mucosae, and those of CCN2 in dog, minipig, rat, and buffalo oral mucosae were equivalent to the expression intensities in human mucosa. The expression of fibrosis-related molecules in the dog oral mucosa optimally mimics the human condition, suggesting its suitability with regard to histopathology as an animal model for the study of OSF.