Chondrogenic differentiation of cultured rat mesenchymal stem cells from bone marrow

Background Mesenchymal stem cells (MSCs) in the bone marrow retain the capacity to proliferate and differentiate along multiple connective tissue lineages, including cartilage. The aim of this study is to induce cultured-expanded rat MSCs derived from bone marrow to express the morphology and protein production of chondrocytes. Materials and methods The characteristics of MSCs and chondrogenic cells were determined morphologically, immunohistochemically, and by transmission electron microscopy. Results MSCs were spindle shaped with irregular processes, and were positive for CD44 and CD105 and negative for CD34. Chondrogenesis is induced by culturing the rat MSCs in monolayer in the presence of a defined chondrogenic medium that includes 100 nm dexamethason and 10 ng/ml TGF-β3. The results showed that the cells changed their morphology within 5 days and became positive for collagen II within 3 weeks after differentiation. Also, the chondrogenic cells showed the structural organelles of protein-synthesizing cells by electron microscopy. Conclusion These results indicated that TGF-β3 can induce rat MSCs to differentiate in vitro into chondrogenic cells. Therefore, chondrogenic cells cultured from bone marrow sources are potentially valuable for repairing injured cartilage.