In vitro proliferation of human bone marrow mesenchymal stem cells employing donor serum and basic fibroblast growth factor

A method for the in vitro proliferation of human bone marrow mesenchymal stem cells (MSCs) employing a medium not containing fetal calf serum (FCS) was developed for a regenerative medicine of cartilage using MSCs. Without using density-gradient centrifugation, the bone marrow aspirate was poured into a dish (6.0 x 10(5) nucleated cells/cm(2)) with DMEM medium containing 10% serum (FCS or donor serum) and basic fibroblast growth factor, and incubated at 37 degreesC under a 5% CO2 atmosphere. The density of adhesive cells incubated with the medium containing human serum and basic fibroblast growth factor ( 10 ng/ml) almost reached confluence at 19d and was 1.4 - 2.7 times that in the medium containing only FCS. The density of cells incubated with the medium containing only human serum was 0.1 - 0.6 times that in the medium containing only FCS. The content of CD45(-) CD105(+) cells among the cells harvested after a 19-d incubation in the medium containing human serum and basic fibroblast growth factor was higher than 90%. This high content and chondrogenic activity, which was confirmed by pellet cultivation and staining with Safranine O, were maintained even after further subcultivation in the medium to 17 population doubling levels. Consequently, this method might be applicable to in vitro proliferation of MSCs for the regeneration of cartilage.