Comparative Investigation of Mesenchymal Stem Cells Isolated from the Bone Marrow and Fetal Liver of Mouse and Rat

We studied the properties of cells forming fibroblast colonies from the bone marrow and fetal liver of mouse and rat. Bone marrow and fetal liver cells formed colonies in vitro including fibroblasts as well as a considerable proportion of macrophages. The colonies formed from bone marrow and hepatic cells of rat differed from the murine ones by a higher proportion of fibroblasts. Most colonies derived from the bone marrow of both mouse and rat included a fraction of cells expressing alkaline phosphatase, and hence, capable of osteogenic differentiation; the colonies derived from the fetal liver included low proportions of such cells. The cell layers derived from the colony-forming fibroblasts of both bone marrow and fetal liver of mouse maintained hematopoiesis in the peritoneal cavity of irradiated mice, which indicated that these progenitor cells can form hematopoietic microenvironment.