Intra-articular use of a platelet-rich product in normal horses: Clinical signs and cytologic responses

Abstract

Objectives: (1) To report the clinical and synovial effects of a platelet-rich product (PRPr) in normal equine joints, (2) to assess the persistence of platelets within synovial fluid after intra-articular injection, (3) to compare responses to different preparations of that product, and (4) to evaluate a gravity filtration system for PRPr preparation in horses. Study Design: Experimental. Methods: A platelet-rich saline product (PRPr) was prepared from 7 normal horses using a proprietary preparation device and was divided into 3 treatments: resting, CaCl2-activated (23mM, final), and bovine thrombin-activated (10U/mL, final). Each horse had 3 concurrent randomly assigned intra-articular PRPr treatments administered in their metacarpophalangeal/metatarsophalangeal joints; the fourth limb was injected with saline (0.9% NaCl) solution as a control. Clinical assessments, cytologic analysis of synovial fluid and hemograms were performed at 6, 24, 48, and 96hours after injection. PRPr composition and growth factor content were analyzed. Results: The gravity filtration system produced a moderately concentrated PRPr. At 6 and 24hours, when compared to control values, all PRPr treatments caused a significant increase in synovial WBC concentration (P