Effects of platelet rich plasma and acellular bone marrow on gene expression patterns and DNA content of equine suspensory ligament explant cultures

REASONS FOR PERFORMING STUDY: Suspensory ligament (SL) desmitis is a common source of lameness. The results of this study will determine if blood-derived products stimulate SL matrix synthesis and have potential as regenerative therapies for SL desmitis OBJECTIVES: To determine if various blood-based biological products including plasma, blood, PRP, platelet poor plasma (PPP) and ABM aspirate stimulates anabolic and/or catabolic pathways in suspensory ligaments (SL). METHODS: The body of the SL was harvested from 6 horses and used to establish explant cultures. Explants were cultured in plasma, blood, PRP, PPP or ABM at concentrations of 10, 50 or 100%. Anabolic responses were assessed by use of quantitative PCR for collagens type I and III, cartilage oligomeric matrix protein (COMP) and decorin. Total DNA and collagen protein content were also measured. Catabolic reactions were measured by quantitative PCR for matrix metalloproteinases 3 and 13 (MMP-3, MMP-13). Results: Acellular bone marrow aspirate at 100% stimulated decorin and COMP mRNA synthesis more than all other treatments at all concentrations. No treatment at any concentration stimulated the catabolic gene MMP-13; only 50% ABM stimulated MMP-13 mRNA expression. CONCLUSIONS: Acellular bone marrow is indicated, and might be preferred to plasma, blood or PPP, as a blood-based biological source for SL tissue regenerative therapy. Long-term, placebo controlled case studies are indicated to determine if ABM aids in recovery from SL desmitis. POTENTIAL RELEVANCE: Bone marrow aspirate is an autogenous, readily available biological source for SL regenerative therapy where the aim is to stimulate matrix synthesis.