| Background and Objective: Oral cavity is an important organ for human feeding, and oral mucosa is a moist lining mouth layer which has functions of protection and feeling. Mouth mucosa damage can be caused by frequent maxillofacial trauma and unexplained oral ulcer. Oral mucosa damage could affect human chewing, swallowing, and language activities, which could also severely influence the life and social activity and even psychology of patients. However, the commonly used drugs that promote mucosal healing were mainly anti-infective drugs in clinic. The effective drugs of promoting mucosal healing were rare. Therefore, finding an effective, safe, convenient method applied to promote mucosal healing may greatly improve the patients’ quality of life.Many studies demonstrated that epithelial-to-mesenchymal transition(EMT) was closely related to skin wound healing, however the role of EMT in oral mucosa wound healing was still undefined. EMT is involved with a variety of signal molecules, signal transduction pathway and transcription factors. The research of the relationship of mucosa healing and EMT would provide new target for therapeutic method for mucosal healing. Transforming growth factor-β1(TGF-β1) is known as an inducer of EMT which has been most widely studied. In our study, we observed the EMT phenomenon in the process of tongue mucosa tissue of rats, and detected the effect of TGF-β1 on tongue mucosa of rat wound healing and oral mucosa epithelial cells, and then further preliminary analyzed the relationship of mucosa healing and EMT.Methods: Experiment One:Three-mm wounds were introduced into the back of tongue mucosa of each Wistar rat aged 7-8 weeks using a dulled disposable biopsy punch. Wounds were allowed to heal for 0, 1, 2, 3, 4 or 10 days. Tongues were collected from 8 rats per time point after humane euthanasia by over-dose of anesthetic. We could observe tissue healing process by HE staining, meanwhile, detect the expression of EMT related protein E-cadherin(E-cad),Vimentin and Fibroblast specific proteins(FSP1) in tongue mucosa during wound healing by immunohistochemical fluorescence. Experiment Two: Animal model were taken preparation as above, wounds were given drug locally per time point. Rats were randomly divided into TGF-β1 gel group, gel group, and blank control group. After 0, 2, 4, 6 or 8days of treatment, each group was selected 8 rats randomly for collected tongues, analyzed wound healing rate between groups, observing the EMT related proteins above by indirect immunofluorescence. Scratch experiment in vitro was used to observe the influence of TGF-β1 on human immortalized oral epithelial cells(HIOEC).Results: Experiment One: The expression of E-cad in rat tongue mucosa postoperative 2d or 4d was less than postoperative 0d or 1d, and mesenchymal cell specific protein Vimentin, FSP1 expressed in epidermal basal layer. E-cad expression in 10 th day when wound healed completely is close to 0d. Experiment Two: After 8days of treatment, TGF-β1 gel group healed faster than the gel group and the control group(P <0.05); At each point, the number of cells which expressed Vimentin and FSP1 in the basal layer of wound edge zone has no statistical different; Cell Scratch test showed that scratch healed faster than the control group after stimulated by TGF-β1.TGF-β1 group which was faster than group had almost healed at 96 h.Conclusion: EMT occurred during wound healing in the rats tongue mucosa; TGF-β1 could enhance the migratory ability of oral mucosa epithelial cells in vitro, which could also promote wound healing in rat tongue mucosa. However, further investigation is required, exploring the linkage between the role of TGF-β1 in promoting mucosa wound healing and EMT. |
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