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[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.