Jiarong Liu, Jiajia Zhao, Shue Li, Lijuan Zhu, Ran Yu, Yinying Qu, XiaoDan Zheng, Lin Liu and Lili Chen
Oral mucosal wounds heal faster with minimal scar compared with cutaneous wounds. In order to reduce the effect of environmental factors and find the expression difference of growth factors in oral and dermal wound, this study created the following rat wound model. The oral mucosa was firstly transplanted to left abdominal skin and after the wounds healed, a line-like full-thickness excisional wound was created on the mucosal tissue site and the right abdominal skin. Full-thickness tissue biopsies were collected from the wounds including 5 mm of the surrounding tissue at 12 hrs, 1 d, 3 ds, 5 ds and 7 ds after wounding. Quantitative real time PCR and immunohistochemistry were used to analyze the expression level of TGF-β1, TGF-β3 and VEGF. In order to find the reaction of oral and dermal fibroblasts to different growth factors, the effects of TGF-β1, TGF-β3 and VEGF on migration and proliferation of both cells were also evaluated in vitro. Results showed that reduced TGF-β1 expressions were found in transplanted mucosal wounds at most time points post injury compared with cutaneous wounds. The TGF-β3 expressions were higher at 3 d while lower at 7 d post injury in transplanted mucosal wounds. VEGF levels generated in transplanted mucosal wounds remained at low levels at 5 d and 7 d post injury. In vitro study found that both oral and dermal fibroblasts migration could be promoted by TGF-β1 and TGF-β3, while the migration of oral fibroblasts could not promoted by VEGF suggesting that oral fibroblasts reacted differently to growth factors. The in vitro proliferation experiment showed that both cells could be promoted by the three growth factors at different concentrations. Our results suggested that the rapid healing and the absence of scars in oral mucosa are directly related to its intrinsic characteristics and not to environmental factors.