A Preliminary Study On The Mechanism Of Botulinum Toxin Type A In The Treatment Of Hypertrophic Scar

Objective: Extract and culture human hypertrophic scar fibroblasts(HSFB)to investigate the effects of Botulinum toxin type A(BTX-A)on proliferation,differentiation and apoptosis of hyperplastic scar fibroblasts,and further explore the specific mechanism of action.Methods: The tissue specimens of this experiment were derived from 10 hypertrophic scar patients with plastic surgery in the First Affiliated Hospital of China Medical University from October 2018 to October 2019.The tissue block adherent method was used to extract and culture fibroblasts.Different concentrations of BTX-A were used to act on fibroblasts.The experiment was divided into BTX-A group and control group.Cell morphology and proliferation were observed in each group.The apoptosis of each group was detected by flow cytometry using Annexin V-PI double staining.The expression of p-P38,total P38,and ?-SMA protein in each group was detected by Western Blot.Results: 1.After the action of BTX-A on fibroblasts,the cell morphology changed and the volume became smaller,tending to be round from the original long spindle shape.2.Fibroblasts was treated with different concentrations of BTX-A(1U/m L,5U/m L,10U/m L,20U/m L),and cell proliferation was detected by CCK-8 on days 1,3,5,and 7,respectively.The number of cells in the 10U/m L group and 20U/m L group was significantly lower than that in the control group on the first day.On the third,fifth and seventh day,the number of cells in the BTX-A group was significantly lower than that in the control group.3.After 48 h of treatment with 20U/m L BTX-A,Annexin V-PI double staining was used to detect the apoptosis of fibroblasts cells in each group.The results showed that the apoptosis rate of BTX-A group was 33.09±5.40%,while that of control group was 4.19±0.50%.4.After fibroblasts was treated with 20U/m L BTX-A,Western Blot was used to detect protein expression in each group.The results showed that the expression levels of p-P38 and ?-SMA in BTX-A group were lower than those in the control group,and the expression levels of total P38 protein were not significantly changed.Conclusion: 1.BTX-A can inhibit the proliferation and differentiation of HSFB and accelerate its apoptosis;2.BTX-A can act on the P38 MAPK signaling pathway of HSFB and inhibit the phosphorylation of P38 protein.