Macroscopic and histomorphometric evaluation of different healing stages of skin wounds in horses treated with leukocyte-poor platelet-rich plasma

Abstract

Skin injuries are frequent in horses, and one of the treatments used for such injuries is the platelet-rich plasma (PRP). The objective of this experiment was to macroscopically and microscopically investigate the process of healing by second intention in skin wounds of eight healthy gelding crossbred horses treated (T) or untreated (UT) with a single dose of leukocyte-poor PRP (LP-PRP). Three square-shaped wounds were induced in both gluteal regions. After 12 h of wound induction, 0.5 mL LP-PRP was administered in each border of the lesion in one of gluteal region. Contralateral wounds were UT. Six skin biopsies were obtained with a 6-mm Punch. Macroscopic variables of one of the non-biopsied wounds were evaluated. Samples were processed for histomorphometric evaluation. No difference was observed between the time required for wound closure in the two groups. Histomorphometric analysis performed 14 days after wound induction revealed higher (p = 0.034) angiogenesis and number (p = 0.0179) of total leukocytes in T wounds. Fibrocytes numbers increased significantly (p = 0.023) on day 7 after injury in the UT group. General microscopic evaluation performed independently of scores and morphometric analysis revealed that the majority of the T wounds showed better healing variables in the sections analyzed after complete macroscopic closure of the wound. A single injected dose of LP-PRP 12 h after wound induction in horses does not interfere with the wound healing process but reveals that majority of the T wounds exhibit better healing histomorphometric characteristics.