The use of Botulinum toxin-a injection for facial wrinkles: a histological and immunohistochemical evaluation.

Botulinum toxin (BTX)-A has been used for years in the reduction of facial wrinkles; however, histological and immunohistochemical changes after its use were not previously investigated. To evaluate histological and immunohistochemical changes after BTX-A injection for facial wrinkles, sixteen volunteers, with wrinkles on the upper third of the face, were subjected to single injection of BTX-A. Skin biopsy specimens were obtained from peri-orbital wrinkle site (crow's feet area) before and after 3 months of BTX-A injection. Using histological and immunohistochemical evaluation coupled with computerized morphometric…