Influence And Research Of Mitomycin C On Laryngotracheal Stenosis Of Rabbit

The laryngotracheal trauma, tracheotomy in high position, and trachea cannula give rise to the over hyperplasia and contracture of cicatrix, which commonly cause the laryngotracheal stricture. The main method of current treatment is firstly to apply the endoscope laser surgery making the excision of cicatrix, secondly to implement the airway stenting to maintain the circulation of air in the trachea, but it has a certain recurrence rate. The medical treatment take the advantages of easily operating, low trauma and well accepted by the patients. Among the medical treatment, the mitomycin C is much cheaper and has low side effect. The mitomycin C has always been mostly applied for the research towards the treatment of laryngotracheal stricture.Speaking of the basic research of laryngotracheal stricture, researchers generally agree the close relationship between the formation of cicatrix and the change of series cell growth factors. Among which, the transforming growth factorβ1 (TGF-β1) and the basic fibroblast growth factor (bFGF) are the most closely related. While among the formation process of cicatrix, the relationship of different cell growth factors is complex. We need to fulfill the further research of mitomycin C’s main effect.This paper mainly conduct the research of the availability and practicability of mitomycin C curing the laryngotracheal stricture through building a simple and stable rabbit laryngotracheal model and seting the mitomycin C as the only variation factor. The research also conducts the effect of mitomycin C restraining the fiber cellular proliferation in the initial step.PART 1 ESTABLISHMENT OF RABBIT MODEL OF LARYNGOTRACHEAL STENOSIS AND MONITORING THE EFFECT OF MITOMYCIN C TREATMENTObjective To observe the stability of rabbit model and observe the effect of mitomycin C on laryngotracheal stenosis of rabbit.Methods Rabbits were divided into six groups according to simple randomization:control group, model group,0.5mg/ml low-dose group,2mg/ml middle-dose group and 5mg/ml high-dose group. The model of rabbit laryngotracheal stenosis was build by scraping the laryngotracheal mucosa. One rabbit of the model group were randomly selected and observed by fibrolaryngoscope in 9,18 days after opreration. All rabbit in the drug group received topical application of mitomycin C to the wound surface of larygotracheal.The stenosis tissue of larygotracheal was removed to observe the stenosis degree at 20 days after opreration.Results Compared with control group, model group and three treatment Group appear obvious laryngotracheal stenosis(P<0.05). The stenosis degree of 2mg/ml middle-dose group and 5mg/ml high-dose group was significantly lower than model group (P<0.05),but no visible difference between model group and 0.5mg/ml low-dose group (P>0.05); there is no significant difference between 2mg/ml middle-dose group and 5mg/ml high-dose group(P>0.05); No significant difference in the sub-groups of each treatment group(P>0.05).Conclusion The model of rabbit laryngotracheal stenosis is stable and effective, it’s easy to operate, and is applicable to various experimental studies about laryngotracheal stenosis. Mitomycin C has a good picture in the perspective of preventing laryngotracheal stenosis.PART 2 MECHANISMS STUDY OF MITOMYCINC TO TREAT LARYNGOTRACHEAL STENOSIS IN RABBITObjective To observe mechanism of mitomycin C on fibroblasts cultured in vitro.Methods Fibroblasts cultured from the stenosis tissue of the model group in part 1, were cultured in vitro with six different concentrations of mitomycin C(0、2.5、12.5、50、100、200mg/L). Meanwhile, fibroblast apoptosis difference was detected by flow cytometry. In addition, expression changes of bFGF and TGF-β1 protein in these 6 groups were detected by Western blot, their mRNA were detected by FQ-PCR.Results With increasing concentration of mitomycin C, fibroblasts early and late-stage apoptosis increased significantly, TGF-β1, bFGF protein and their mRNA expression was significantly decreased.Conclusion Mitomycin C can significantly inhibit the cell proliferation of fibroblast and reduce the expression of TGF-β1 and bFGF. It has a good picture in the perspective of inhibiting the cell proliferation of fibroblast, and preventing laryngotracheal stenosis.