Abstract: Objective: To construct a Sprague Dawley (SD) rat oral submucosal fibrosis model by injecting arecoline solution under the mucosa. Methods: 20 SD rats were randomly divided into an experimental group and a control group. The rats were injected with arecoline solution under the buccal mucosa for modeling in experimental group, while the rats were injected with physiological saline in control group. After 10 weeks of treatment, the oral mucosa color and weight of rats were observed, and the passive mouth opening was measured; hematoxylin-eosin (HE) and Masson staining were used to observe pathological changes in mucosal tissue; Immunohistochemical staining and real-time fluorescence quantitative PCR were used to detect the protein and gene expression levels of α-Smooth muscle action (α- SMA) and platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) in mucosal tissue. Results: In experimental group, white lesions appeared on the buccal mucosa of the rats, and the mouth opening decreased (P＜0.000 1); epithelial atrophy and deposition of collagen fibers in the lamina propria appeared in mucosal tissue; protein and gene expression levels of α-SMA significantly increased (P＜0.000 1), while the expression levels of CD31 significantly decreased in mucosal tissue (P＜0.000 1). Conclusions: The submucosal injection method of arecoline can construct an OSF rat model with typical symptoms and significant pathological changes.

Key words: oral submucosal fibrosis, arecoline, animal models, collagen deposition