[Proliferation and differentiation characteristics of human bone marrow mesenchymal stem cells during ex-vivo expansion].

AIM: To investigate the effects of ex-vivo expansion on proliferative ability, pluripotentiality and other biologic characteristics of human bone marrow mesenchymal stem cells(MSCs).

METHODS: MSCs were isolated from human costal bone and passaged under the same culture conditions. At each passage, the characteristics of proliferation kinetics, osteogenic, chondrogenic, adipogenic differentiation potential were analyzed, and cell morphology, surface markers and cell cycle were investigated as well.

RESULTS: The proliferative ability and osteogenic, adipogenic differentiation potential decreased during culture expansion, while chondrogenic differentiation potential had no significant changes. MSCs maintained their multiple differentiation potential during their life-span. For each passage, the positive ratio of CD29, CD44, CD105 were all above 90% and the negative ratio of CD14, CD34, CD45 were below 4%.

CONCLUSION: Culture expansion causes MSCs to gradually lose their stem cell properties. During ex-vivo expansion of hMSCs, the osteogenic and adipogenic differentiation potential are more likely to lose than chondrogenic differentiation potential. Multiple differentiation potential is conserved longer than self-renewal capacity. MSCs before 7th passage can be a valuable subject for basic research and clinical application.