A recent study reported that
Botulinum toxin type A (BTXA) could inhibit the growth of
hypertrophic scars and improve their appearance. However, the mechanism of BTXA's action on
hypertrophic scars is still unknown. Some in vitro studies had shown BTXA could alleviate
hypertrophic scars by acting on the
biological behavior of fibroblasts, but there are few in vivo experiments, especially animal model experiments, supporting these findings. The aim of the study reported herein was to investigate the effect of BTXA on
collagen deposition on
hypertrophic scars in a rabbit ear model and partially clarify the mechanism of BTXA on the
hypertrophy of
scars. The rabbit
hypertrophic scar model was used and eight rabbits were employed. BTXA was injected into the
hypertrophic scar tissue of one ear; and the other ear in the same rabbit was the control without BTXA injection. The
scar thickness and deposition of
collagen was examined through immune histochemistry including haematoxylin and
eosin (H&E) and Masson trichrome staining. The thicknesses of
hypertrophic scars in the BTXA treatment group were obviously lower than in the control groups (P < 0.01). H&E and Masson staining showed that
collagen fibers were stained blue. Compared with the treatment group, the
collagen fibers were thicker and the arrangement of
collagen fibers were disordered in the control group. This study used the rabbit ear model of
hypertrophic scars to assess the effects of BTXA on
scar hypertrophy. The application of BTXA may be useful for inhibiting
hypertrophic scars.