[Effect of botulinum toxin type A injection on hypertrophic scar in rabbit ear model].

OBJECTIVE: To investigate the effect of botulinum toxin type A (Botox A) injection on hypertrophic scar in rabbit ear model. METHODS: The hypertrophic scar model was established in 16 Japanese rabbits' ears. These wounds were divided into two groups as group T (treated with Botox A, n = 48) and group S (not treated, n = 48). The wounds healing times and scar hypertrophy were observed with 8 specimen of normal skin at the rabbit ears as sham group B. HE stain was used to assess the hypertrophic index (HI). The expression of collagen I and III was tested by western-blot. The cell cycle of fibroblasts was studied by flow cytometry. RESULTS: The HI was significantly lower in group T than in group S (P < 0.01). The expression of collagen I and III, as well as the ratio of I to III, was markedly stronger in group S than in group T (P < 0.01). Compared with group T, more fibroblasts were in G2-M in group S and fewer in G0-G1 (P < 0.05). CONCLUSIONS: Local injection of Botox A can inhibit the formation of hypertrophic scar and the activity of fibroblasts in rabbit ear model. It can significantly decrease the expression of collagen I and III in hypertrophic scar, as well as the ratio of collagen I to III. It serves as the basis for the treatment of hypertrophic scar with Botox A.