Botulinum Toxin Type A Inhibits Hypertrophic Scar Formation In A Rabbit Ear Model

Background:Hypertrophic Scar(HS)is a refractory skin disease caused by major physical damage or other inflammation.Some reports found that botulinum toxin type A(BTXA)could be an alternative treatment of the HS.Therefore,the authors studied the effects of BTXA on the treatment of HS and the dose response of BTXAObjective:The purpose of the experiment is to investigate whether BTXA affects the growth of HS in a rabbit ear model and explore the mechanisms of BTXA on treating HS and the effect of dose of BTXA.Methods:Hypertrophic Scars were harvested from the ears of 18 young adult New Zealand big-eared rabbits and treated with BTXA or triamcinolone acetonide(TAC)in vivo experiment.The Hypertrophic Index(HI)was measured by histological examination.Collagen fibrils were checked by Sirius red straining,and the cell nucleuses of fibroblasts were checked by Ki67.Results and Conclusion:The HI of hypertrophic scars with BTXA treatment was lower than that with phosphate-buffered saline treatment(P<0.05).Compared with the TAC treatment group,the efficacy of treatment with the middle dose of BTXA(1.0,1.5IU)had no significant difference,as shown by Sirius red staining and immunohistochemistry Ki67.These results demonstrated that BTXA effectively improved the appearance of hypertrophic scars and inhibited the formation of collagen fibrils and fibroblasts in vivo.Treatment with the middle dose of BTXA achieved similar efficacy as TAC treatment,indicating that BTXA might be useful for inhibiting hypertrophic scars and worth investigating further.