Immunohistochemical Measurement of TGF-β1 and Factor VIII in the Skin of Horses Treated with Leukocyte-poor Platelet-rich Plasma: A Randomized Controlled Trial

Abstract

Platelet-rich plasma (PRP) is a treatment used for several diseases of various species and different body regions. However, there is controversy about its therapeutic efficacy. The objective of this experiment was to immunohistochemically evaluate the expression of transforming growth factor beta 1 (TGF-β1) and factor VIII during the healing period of skin treated with leukocyte-poor platelet-rich plasma (LP-PRP) in seven healthy gelding crossbred horses. This study was a randomized controlled clinical trial. Wounds were surgically induced in gluteal region (treated group), and LP-PRP (0.5 mL) was injected into all borders of the wounds 12 h later. The contralateral region (untreated) was adopted as the control group. Five skin samples were obtained from the treated and untreated groups for immunohistochemical analysis. The last one was collected upon wound closure. We hypothesized that the treated wounds would exhibit higher expression of both TGF-β1 and factor VIII than the untreated wounds. There was no difference between groups in TGF-β1 immunostaining. However, a difference was observed between groups in immunostaining of blood vessels for factor VIII. This difference (P < 0.05) occurred after macroscopic wound closure, with larger numbers of vessels stained in the treated wounds. The administration of a single dose of LP-PRP 12 h after wound induction in horses is not effective compared with the physiological healing of horse skin. Further research should not only take into consideration the association of the platelet-rich component with stem cells, which, in general, have provided adequate responses, but also evaluate other proteins present in PRP besides those typically studied.