Equine marrow-derived mesenchymal stem cells: isolation, differentiation and culture optimization

Most studies regarding the marrow-derived equine mesenchymal stem cells (MSCs) have mainly focusedon the cell transplantation without considering the capacity of differentiation and in vitro requirements of thecells. These concerns were investigated in the present study. Equine MSCs were isolated from the sternalmarrow aspirates and expanded through two successive subcultures. Passage-2 equine MSC cultures werethen treated with appropriate supplements in order to examine the cell osteogenic, chondrogenic andadipogenic differentiation potential. Furthermore, the culture of the cells was investigated in terms of theoptimal concentration of fetal bovine serum (FBS) and the initial cell-seeding density. Additionally, a growthcurve was plotted for the cells to study their growth characteristics. According to our findings, equine MSCswere easily generated specialized bone, cartilage and adipose cell lineages as confirmed by specific stainingand RT-PCR analysis. Moreover, the cells exhibited rapid expansion when being cultivated in the mediumwith 15% FBS at 100 cells/cm2. Growth curves indicated that these cells rapidly entered the log phase after abrief lag (adaptation) period. In summary, marrow-derived equine MSCs possess tripotent differentiationcapacity and rapid growth rate in the appropriate culture conditions.