Evaluation of isolation methods and culture conditions for rat bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (bMSCs) are multipotent and preferred for cell therapy. However, the content of bMSCs is very low. To propagate a large number of primary bMSCs rapidly has become a prerequisite for bMSC study and application. Different methods of isolating and culturing bMSC were used and compared among groups: bMSCs of group A are isolated using direct adherence method and cultured by conventional medium changing; of group B are isolated using direct adherence method and cultured by low volume medium changing; of group C are isolated using density gradient centrifugation and cultured by conventional medium changing; of group D are isolated using density gradient centrifugation and cultured by low volume medium changing. The average population doubling time (PDT), average generation time and the cumulative cell doubling level were calculated for every group. bMSCs cultured with complete medium containing 10, 11 and 15 % FBS were allocated into group a, b and c separatedly. Cell numbers were counted everyday under a microscope, the population doubling level curve was plotted and PDT was calculated. The growth curve of bMSC in group a, b and c was made. Both density gradient centrifugation and direct adherence methods obtained relatively pure bMSCs. A larger quantity of primary bMSCs were obtained by direct adherence. bMSC proliferation was faster when cultured via the low volume medium changing method at a serum concentration of 11 % than the other methods. Isolating bMSC by direct adherence and culturing by low volume medium changing at a serum concentration of 11 % is preferential for bMSC propagation.