Experimental Study Of Botulinum Toxin Type A On Inhibiting Biological Function Of Hypertrophic Scars Fibroblasts

Objective:The aim of this study was to observe the expression of focal adhesion kinase?FAK?on the fibroblasts of hypertrophic scars as well as to observe the different expression of the FAK and related proteins in fibroblasts after treatment with botulinum toxin type A.To explore the effect of botulinum toxin type A on the proliferation of fibroblasts of hypertrophic scars,apoptosis,and migration.The study was conducted in order to further explore the mechanism of botulinum toxin type A in inhibiting hypertrophic scars,so as to provide a theoretical basis for the clinical application of botulinum toxin type A in the inhibition of hypertrophic scars.Method:Experimental tissue specimens were collected from patients from October2016 to February 2018 in the Plastic Surgery Department of the General Hospital of Northern Theater.Patients included in the study were free of systemic diseases and had all received surgical resection and treatment to inhibit hypertrophic scars prior to surgery.Through preoperative clinical diagnosis and post-operative pathological examination,all patients were diagnosed with hypertrophic scars.Six patients with hypertrophic scar tissue after surgical resection were randomly selected as the experimental group.Control group specimens were extracted from the surgical area.These specimens consisted of superfluous normal skin tissue and normal scar tissue,after local skin flap transfer.Fibroblasts were isolated and cultured in vitro,then the botulinum toxin type A at 0.05 U and 0.1 U concentration was used to interfere with the proliferation of hypertrophic scar fibroblasts.Botulinum toxin was not used in the control group.The effect of botulinum toxin type A on the proliferation of hypertrophic scar fibroblasts was observed by MTT assay.Annexin V/PI staining was used to observe the effect of botulinum toxin type A at different concentrations on the apoptosis of hypertrophic scar fibroblasts.The effect of botulinum toxin type A on the migration of hypertrophic scar fibroblasts was observed by Transwell experiment.Western blot experiment was used to observe the expression of focal adhesion kinase?FAK?in normal skin,normal scar,and hypertrophic scar tissues.Botulinum toxin type A at different concentrations was applied to hypertrophic scar fibroblasts cultured in vitro,then the expression of FAK and related proteins in the fibroblasts was again detected by Western blot experiment.Experimental data and results were recorded and statistical analysis was made.Results:MTT results showed that the proliferation of hypertrophic scar fibroblasts was inhibited by botulinum toxin type A at different concentrations,and the inhibition of 0.1 U concentration was stronger than that of 0.05 U.Flow cytometer showed that after Annexin V/PI staining,the apoptotic rates of hypertrophic scars fibroblasts interfered with botulinum toxin type A at 0.05 U and 0.1 U.In the experimental group,concentrations were 3.8%and 6.9%.The control group was 1.2%.Transwell experiment results showed that the migration of hypertrophic scar fibroblasts was inhibited by botulinum toxin type A,and the concentration of 0.1U was stronger than that of 0.05 U.Western blot results showed that the FAK^p-Tyr397,a phosphorylated form of focal adhesion kinase,was differentially expressed in hypertrophic scar fibroblasts.The total expression level of the focal adhesion kinase in hypertrophic scar fibroblasts was not affected by botulinum toxin type A at different concentrations,but the expression level of FAK^p-Tyr397-Tyr397 was lower than in the control group.The expression levels of proliferation and apoptosis-related protein CDK4 and Bcl-2 were lower,and the effect of botulinum toxin type A at a concentration of 0.1 U was more obvious than at a concentration of0.05 U.Conclusions:1)Botulinum toxin type A can inhibit the proliferation of hypertrophic scar fibroblasts.2)Botulinum toxin type A can promote the apoptosis of hypertrophic scar fibroblasts.3)Botulinum toxin type A can inhibit the invasion and migration of hypertrophic scar fibroblasts.4)The expression of FAKp-Tyr397,a phosphorylated form of FAK,was increased in hypertrophic scar fibroblasts.5)Botulinum toxin type A can inhibit the expression of FAKp-Tyr397 and related proteins in hypertrophic scar fibroblasts.