The Antimicrobial Peptide Nal-P-113 Exerts a Reparative Effect by Promoting Cell Proliferation, Migration, and Cell Cycle Progression

OBJECTIVE: The primary purpose of this study was to evaluate the reparative efficacy of a novel antimicrobial peptide, Nal-P-113, in shortening the healing time of oral mucosal ulcers by promoting cell proliferation and migration and accelerating the cell cycle. METHODS: Cell counting kit-8 (CCK-8) and wound-healing assays were used to evaluate the proliferation and migration of human immortalized oral epithelial cells (HIOECs). The cell cycle distribution of HIOECs was analyzed by flow cytometry. Additionally, the RNA levels of EGF, FGF-2, and TGF-β1 of HIOECs were assessed by real-time PCR. Rats were divided into three groups randomly: (a) blank control group; (b) 20 μg/mL Nal-P-113; and (c) 10 ng/mL rhEGF. An oral mucosal ulcer was induced in every rat by the application of 30% acetic acid. An immunohistochemical assay was used to assess the expression of EGF, FGF-2, and TGF-β1 in the rat oral mucosa. RESULTS: In the CCK-8 assay, the optical density values in the Nal-P-113 and rhEGF groups were found to be significantly higher than that in the blank control group. In addition, the scratch areas in the Nal-P-113 and rhEGF groups were found to be significantly smaller (P<0.05). Cell cycle analysis showed that Nal-P-113 accelerated the entry of HIOECs into the S phase and expedited their cell cycles. The RT-PCR results suggested that Nal-P-113 upregulated the RNA levels of EGF and FGF-2 but downregulated that of TGF-β1 at 24 h and 48 h. Lastly, the immunohistochemical assay verified that Nal-P-113 changed the expression of the above cytokines in rat mucosal ulcers. CONCLUSION: Nal-P-113 promoted the repair of oral mucosal ulcers by increasing the EGF and FGF-2 expression and decreasing that of TGF-β1 in HIOECs, accelerating their proliferation and cell cycle progression. The application of Nal-P-113 might serve as an effective therapeutic approach for recurrent aphthous stomatitis.