Effect of dexamethasone on levels of inflammatory factors and EGF mRNA in rabbits suffering from oral ulcers

Abstract

Purpose: To investigate the therapeutic effect of dexamethasone on rabbits suffering from oral ulcers, and the underlying mechanism(s) of action. Methods: A rabbit model of oral ulcer was established by applying 40 % glacial acetic acid solution to the oral buccal membranes of the animals. Three groups of rabbits were used. Changes in area of the oral ulcer were recorded after dexamethasone administration. Levels of epidermal growth factor (EGF) were assayed using reverse transcription PCR (RT-PCR), while MDA levels and expression levels of IL- 6, IL-8 and TNF-α were determined by enzyme-linked immunosorbent assay (ELISA). Local histopathological changes were examined histologically with the aid of hematoxylin and eosin (H & E) staining. Results: There were reductions in ulcer areas in group C on the 2nd, 4th and 7th days of dexamethasone administration, when compared with group B (p < 0.05). The EGF levels in the buccal mucosa of rabbits in groups B and C were significantly higher than those in group A (p < 0.05), while the highest EGF level was in group C (p < 0.05). The levels of MDA, IL-6, IL-8, and TNF-α significantly increased in groups B and C (p < 0.05). Results from H & E staining showed lower levels of inflammatory cells in group C than in group B, with visible proliferation of fibroblast cells and epithelial cells in group C after dexamethasone administration. Conclusion: Dexamethasone accelerates healing of oral ulcer by regulating EGF levels. This finding provides a new approach to the treatment of oral ulcers.