Equine Peripheral Blood‐derived Mesenchymal Stem Cells: Isolation, Identification, Adipocyte Differentiation and Effect of Hyperbaric Oxygen Treatment

Due to their limited proliferation, differentiation and self‐renewal properties, there is some concern regarding the use and nature of mesenchymal stem cells (MSCs) derived from peripheral blood. In this study, we isolated MSCs from equine peripheral blood, monitored their growth and proliferation using CD antigen markers, and ultimately, assessed the effect of hyperbaric oxygen (HBO 2 ) on their concentration and function. MSCs were validated by the mRNA expression of NANOG and SOX2 genes. Freshly isolated MSCs contained a heterogenous population of CD90 positive and negative cells, and under optimum cell culture conditions, only the CD90+ cells expanded and subsequently differentiated into adipocytes. Adipogenesis was confirmed by an increase in mRNA expression of peroxisome proliferator‐activated receptor gamma, and oil‐red‐O staining. Most importantly, there was a 2–8 fold increase in CD90+ cells after three HBO 2 treatments. Furthermore, three horses that did not yield any MSCs prior to HBO 2 treatments resulted in viable cells that could be expanded and differentiated only after exposure to HBO 2 . The results reveal that compared to the adipose tissue, peripheral blood‐derived MSCs contain a relatively lower number of CD90+ cells, which can be mobilized into circulation by HBO 2 resulting in viable MSCs that can proliferate and undergo adipocyte differentiation. This study was funded by the Center of Excellence, UTIA, University of Tennessee, Knoxville, TN.