Background Cold atmospheric plasma (CAP) has gradually drawn attention in the medical field due to its sterilization, promotion of cell proliferation, angiogenesis, and collagen synthesis. However, the application of CAP in the treatment of oral and maxillofacial wounds still needs to be explored.

Objective To investigate the effect of CAP on the healing of oral and maxillofacial wounds in rats and provide experimental evidence for the application of CAP in the treatment of oral and maxillofacial wounds.

Methods CCK-8 assay and cell migration assay were used to evaluate the effects of CAP on the proliferation and migration of rat oral mucosal fibroblasts under different parameters to determine the optimal experimental parameters. Under inflammatory induction conditions, real-time quantitative PCR and Western blot were used to detect the levels of inflammatory-related indicators (TNF-α, IL-1β, IL-6) and repair-related indicators (TGF-β, VEGF, COL1A1) of rat oral mucosal fibroblasts after CAP treatment. A total of 36 SPF male SD rats were selected to establish a cheek penetrating wound model. The experimental animals were randomly divided into control group (n=18) and CAP group (n=18). The wounds in the control group were allowed to heal naturally, while the wounds in the CAP group were treated with CAP daily. The changes in the oral and maxillofacial wound tissues of rats were observed by HE staining, Masson staining and IHC staining. Western blot was used to compare the protein expression of inflammatory-related indicators (TNF-α, IL-1β, IL-6) and repair-related indicators (TGF-β, VEGF, COL1A1) in the two groups.

Results CAP treatment could improve the proliferation and migration ability of rat oral mucosal fibroblasts (P<0.05), and 40%-30S was the optimal experimental equipment parameter. Under this parameter, CAP could significantly down-regulate the expression of inflammatory-related indicators (TNF-α, IL-1β, IL-6) of rat oral mucosal fibroblasts under the inflammatory microenvironment (P<0.05), while significantly up-regulate the expression of repair-related indicators (TGF-β, VEGF, COL1A1). Animal experiments further confirmed that the degree of wound healing in the CAP group was superior to that of the control group. The results of HE and Masson staining showed that the skin and oral mucosa growth at the edge of the wound in the CAP group were more coherent, and collagen fiber proliferation was more obvious. IHC staining showed that the repair-related indicators COL1A1 and VEGF were expressed higher in the skin and oral mucosal tissues of the wound in the CAP group. Western blot results showed that compared with the control group, the expression of inflammatory indicators (TNF-α, IL-1β, IL-6) in the wound tissues of the CAP group animals was relatively lower (P<0.05), while the expression levels of repair-related indicators VEGF and COL1A1 were higher (P<0.05), which was consistent with the results of animal slice observation.

Conclusion CAP treatment can promote the rapid healing of oral and maxillofacial wounds by promoting cell proliferation and migration, alleviating inflammatory reactions, and enhancing the expression of repair-related factors, reducing the risk of delayed wound