OBJECTIVETo investigate the effect of botulinum toxin type A on the expression of substance P (SP), calcitonin gene-related peptide (CGRP), transforming growth factor beta-1 (TGF-beta1) and alpha smooth muscle actin A (alpha-SMA) in wound healing.

METHODS60 rats were randomly divided into group C (control) group L (low-dose) and group H (high-dose), with 20 rats in each group. The wound-healing model was established by excision of four full-thickness skin (1 cm x 1 cm, around the injection site) on the back of all SD rats on the 7th day after BTA injection. The wound size was measured and the expression of SP, CGRP, TGF-beta1 and alpha-SMA in wound granulation tissue was assayed by immunohistochemical staining and computerized image analysis before operation, and 3 days, 7 days and 14 days after operation.

RESULTSAll the wounds healed 14 days after operation. The wound size in L and H group was not significantly different with that in C group on the 3rd day and 7th day after operation. The positive immuno-staining of SP, CGRP, TGF-beta1 and alpha-SMA in group L and H was significantly weaker than those in C group. Meanwhile, the positive immuno-staining of all above substances in H group was weaker than those in L group significantly.

CONCLUSIONSBotulinum toxin type A can decrease the expression of SP, CGRP, TGF-beta1, and alpha-SMA in wound healing in a dose-dependent manner with no effect on the healing time.