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Effects of dexamethasone on the EGF mRNA levels and inflammatory factors in rabbits with oral ulcers

Jianyong Ruan, Daxu Li, Hong Tao, Chunni Deng

Objective: To explore the therapeutic effects of dexamethasone on the rabbits with oral ulcers and the underlying mechanisms of dexamethasone in the treatment of oral ulcers.

Methods: Four of the forty experimental SPF New Zealand rabbits were randomly selected to be used for the identification of oral ulcer model. The rest were randomly divided into three groups: the control group (Group A), the normal saline group (Group B), and the dexamethasone group (Group C), with 12 in each group. The oral ulcer model was established by applying the 40% glacial acetic acid solution to the oral buccal membranes of the rabbits. The changes of the oral ulcers on the model-establishing day and the 2nd, 4th and 7th day after administration were observed. Besides, the epidermal growth factor (EGF) levels in the oral mucosal tissues were examined by reverse transcription PCR (RT-PCR), and the local histopathological changes in the oral ulcers were observed through hematoxylin-eosin (HE) staining.

Results: The ulcer areas in Group C was significantly reduced on the second, fourth and seventh days after dosage when compared with Group B (P<0.05). The EGF levels in the buccal mucosa of rabbits in Group B and C were significantly higher than those in Group A (P<0.05), with a faster increasing pace in EGF levels in Group C when compared with Group B (P<0.05). Results from HE staining showed that inflammatory cells in Group C were significantly decreased compared with those in Group B, the fibroblast proliferation was more obvious in Group C on the 2^nd, 4^th, and 7^th day after administration. Additionally, the epithelial proliferation was better in Group C.

Conclusion: Dexamethasone can significantly improve the symptoms of oral ulcers in rabbits and promote ulcer healing. Consequently, dexamethasone may help accelerate oral ulcer healing by regulating the EGF levels in the process of oral ulcers.