Fetal bovine serum (FBS) has a been standard supplement for mesenchymal stem cell (MSC) culture mediums. Unfortunately the use of this supplement can cause xenogenic reactions when contaminated MSCs are injected into the patient. Researchers have begun searching for alternative autologous and allogenic growth supplements and found hope in platelet lysate. Platelets and their abundant growth factors might allow for cell proliferation. Use of platelet lysate (PL) will eliminate the problem of xenogenic reaction. The use of autologous platelet lysate as a viable medium supplement for equine bone marrow derived MSCs was assessed through this research. This was accomplished by comparing the MSC proliferation in 10% serum supplemented media. FBS and PL were used as the serum sources and a 10% FBS containing heparin medium was also tested as a control for heparin in the platelet lysate supplement. MSC proliferation was assessed using cell counts and colony forming unit assays. Preliminary data showed greater MSC proliferation in the PL and FBS heparin supplemented mediums compared to FBS alone. Flow cytometry was performed to assay for the presence of cell surface markers. The 10% PL group were positive for cell surface markers CD-90 and negative for CD-45 and MHC-II, while the 10% FBS and 10% FBS groups were negative for CD-45 but showed variable results with regards to CD-90 and MHC-II. Each group will be further assessed on its ability to undergo trilineage differentiation. Unaltered MSCs should possess the ability to differentiate into osteocytes, chondrocytes, and adipocytes. ELISA tests will also be performed to determine the concentration of platelet-derived growth factor (PDGF) in platelet lysate samples
