Evaluation of the Short-Term Effects of Intra-Articular Administration of Platelet-Rich Plasma in Horses with Experimentally Induced Synovitis

Introduction: Platelet-rich plasma is used with increasing frequency as a treatment for equine osteoarthritis despite the lack of studies evaluating its effect on the synovial environment, and the exact composition of PRP used is rarely defined. We hypothesized that horses treated with a leukocyte-poor PRP following induction of an acute synovitis would have lower lameness scores and an improved synovial environment with less inflammation and decreased cartilage catabolism.

Materials and Methods: Six horses with no apparent forelimb lameness and minimal osteoarthritis changes on metacarpophalangeal radiographs were studied. Each metacarpophalangeal joint acted as both the control or treatment in this crossover design. Synovitis was induced with 0.5 ng of LPS and serial lameness examination and synoviocentesis were performed. Synovial fluid evaluation included ELISA for collagen cleavage (C2C) and inflammation (PGE2) as well as white blood cell count and total protein. Results were assessed with a two-way ANOVA for repeated measures (p < 0.05).

Results: Treated horses were less lame at 24 and 48 hours compared with controls (p < 0.05). There was a significant increase of cell count and total protein at 8 and 24 hours but no significant difference between groups (p < 0.05). C2C and PGE2 had no significant differences between groups but had a significant increase at 24 hours (p < 0.05).

Discussion/Conclusion: Leukocyte-poor PRP had no deleterious effects on synovial environment and it may be an effective therapy in acute synovitis when corticosteroids are unable to be administered. Serial administration or a leukocyte-rich PRP may have supported hypothesis.

Acknowledgement: Supported by the LSU Charles V. Cusimano EHSP grant.