966 Botulinum toxin suppresses pro-fibrotic effects in hypertrophic scar fibroblasts

Abstract

Hypertrophic scar (HS) is a dermal fibroproliferative disease characterized by the overproduction and deposition of extracellular matrix, cell over-proliferation, enhanced angiogenesis, and enhanced differentiation of fibroblasts to myofibroblasts. Although there has been extensive research on botulinum toxin type A (BTX) treatment for the prevention of HS formation, its effectiveness in the attenuation of skin fibrosis and the related mechanism are unclear. In this study, we investigated the inhibitory effect of BTX on HS-derived fibroblasts (HSFs) in vitro and explored the possible associated molecular mechanism by examining cell proliferation, cell migration, protein expression of scar-related factors, and intracellular signaling. Human scar fibroblasts were cultured and stimulated with BTX. The MTS, scratch, and ELISA, and western blotting were performed to detect changes in fibroblast proliferation, migration, and protein expression of pro-fibrotic factors. Our study revealed that the proliferation, viability and migration of BTX-treated human scar fibroblasts were decreased compared with those of the untreated controls. And protein expression of pro-fibrotic factors including transforming growth factor β1, interleukin-6, and connective tissue growth factor was inhibited by BTX treatment, whereas JNK phosphorylation was activated. Blocking the JNK pathway rescued the inhibitory effects on human scar fibroblast proliferation and the production of pro-fibrotic factors. Therefore it is thought that the suppressive effects of BTX are closely associated with JNK pathway activation. This study showed that BTX has a suppressive effect on extracellular matrix production and scar-related factors in human scar fibroblasts in vitro. Moreover, regulation of JNK signaling played an important role in this process. Our results provide theoretical basis, at the cellular level, for HS treatment.