Marrow Stromal Cells (MSCs) are adult stem cells derived from the bone marrow and can differentiate into lineages of both mesenchymal and nonmesenchymal origin. Human Marrow Stromal Cells (hMSCs) are obtained from a bone marrow aspirate of a healthy donor. Rat Marrow Stromal Cells (rMSCs) are obtained from the bone marrow of femurs and tibias of sacrificed Lewis rats Cohnheim originally discovered MSCs over a century ago; however, it was not until the 1970's that they were more extensively examined. The osteogenic potential of the MSCs was one of the first properties characterized. Following those experiments, additional differentiation potential was discovered when experiments showed that MSCs could differentiate into adipocytes and chondrocytes. Recently, MSCs have captured the interest of numerous scientists due to their potential to differentiate into cells that comprise the central nervous system Although there has been a drastic increase in the use of MSCs in research, the basic properties of cell proliferation and the composition of MSC cultures have not been defined. Our goal was to characterize the heterogeneous population of cells within the rMSC cultures, to compare and contrast hMSCs and rMSCs, to establish standard, reproducible conditions to rapidly expand healthy rMSCs in vitro, and to determine the migration and engraftment potential of rMSCs in vivo
