Effects of platelet-rich plasma on the repair of wounds on the distal aspect of the forelimb in horses

Abstract

Objective - To evaluate the effect of platelet-rich plasma on wounds on the distal aspect of the forelimb in horses. Animals - 6 mixed-breed 10- to 15-year-old mares. Procedures - 3 wounds were created on metacarpal regions in each of 6 horses (n = 36 wounds total). Eighteen wounds were treated with platelet-rich plasma and bandaged, whereas 18 control wounds were similarly bandaged with no prior topical treatment. Decrease in wound surface area and the required number of excisions of exuberant granulation tissue were recorded until complete healing. Tissue specimens were taken from wounds at 1 week for histologic examination and measurement of transforming growth factor-β1 concentrations and at closure for histologic examination, biomechanical evaluation, and measurement of collagen type I and type III mRNA. Results - Platelet-rich plasma favored excessive development of granulation tissue and significantly slowed wound healing at 1, 2, and 3 weeks after surgery. Transforming growth factor-β1 had a 1.6-fold higher concentration in treated wounds, compared with untreated wounds. Histologic, biomechanical and gene expression data did not differ significantly between treated and control wounds. Conclusions and Clinical Relevance - Topical application of autologous platelet-rich plasma did not accelerate or improve the quality of repair of small granulating wounds on limbs of horses. This treatment may better suit wounds with massive tissue loss or, alternatively, chronic wounds that would benefit from a fresh source of mediators to accelerate the healing process.