The potential effect of botulinum toxin type A on human dermal fibroblasts: An in vitro study

Background The use of botulinum toxin type A (BoNT) continues to expand. Some physicians have noted a face-lifting effect after intradermal injection of BoNT, although the effects are controversial. ObjectiveTo investigate the in vitro effects of BoNT on human dermal fibroblasts. Methods The proliferation and toxic effects of BoNT on human dermal fibroblasts were measured. To understand the mechanism of BoNT on collagen production of fibroblasts, procollagen type I carboxy-terminal peptide (PIP) was measured using enzyme-linked immunosorbent assay, and collagen production was monitored using Western blotting. To examine the effect of BoNT on collagen degradation, we evaluated matrix metalloproteinase (MMP) production using gelatin zymography. Results BoNT did not stimulate the proliferation of or show toxic effects on human dermal fibroblasts. Levels of PIP increased significantly in fibroblasts grown in the presence of BoNT, and BoNT upregulated the expression of type I collagen and decreased the production of some MMPs in fibroblasts that prevent collagen degradation. Conclusions This study shows interesting effects of BoNT on collagen production and degradation of human dermal fibroblasts in vitro. This research provides the experimental background for using intradermal BoNT injection for remodeling of dermal tissues in aged skin.