Topical platelet-derived growth factor enhances wound closure in the absence of wound contraction: an experimental and clinical study.

The effects of platelet-derived growth factor (PDGF) on wound healing in animal and human models were investigated. Four 1-cm2 wounds were made on the dorsum of 3 rats. A 0.5-cm punch wound was made behind each ear of 4 patients. Half the wounds were treated daily with vehicle, controls, and the rest were treated with PDGF. Treated wounds closed faster than the controls (animals: 16 +/- 3.2 days vs. 17.8 +/- 2.17 days; p < 0.05) and (patients: 16 +/- 0.67 days vs. 19.5 +/- 0.33 days; p < 0.05). Biopsies were taken at day 20 for polarized light-Sirius red histological analysis. The granulation tissue of PDGF-treated wounds showed fine collagen fibers with weak birefringence, characteristic of immature granulation tissue, deposited throughout the healed wound site. Such a pattern indicates wound closure by reepithelialization and filling in with scar. Control wound biopsies showed a small area of immature granulation tissue surrounded by intact dermal thick collagen fibers with strong birefringence. Such a pattern indicates wound closure by wound contraction. This shows that PDGF enhances wound closure by reepithelialization and the prevention of wound contraction.