[Biological appraisal of human bone marrow mesenchymal stem cells during ex-vivo expansion]

This study was aimed to investigate the characteristics of human bone marrow mesenchymal stem cells during ex-vivo expansion, MSCs were isolated from human bone marrow. At each passage, the characteristics of proliferation kinetics, osteogenic and adipogenic differentiation potential were analyzed, and cell morphology, surface markers were investigated as well. The karyotype analysis was done in different passage cells. The infection HIV, HCV, HBV and TP were detected by ELISA. Mycoplasma contamination in vitro was detected by PCR method. HLA-SBT was used to reanalyze the results of HLA antigens and alleles. STR genetic loci were detected by PCR in the MSC1, MSC2, MSC3 and MSC4. The results indicated that the proliferative ability and osteogenic potential decreased with the increase of passage number during culture expansion. The multiple differentiation potential of MSCs was maintained during their life span. Karyotype analysis showed that MSCs from 4 groups before passage 8 were normal. The expression of CD29, CD44, CD105, CD166 and CD73 were positive. The expression of CD14, CD34, CD45, CD80, CD86 were all negative. SBT was used to identify HLA-A, B, Cw, DRB1, DRPB1, DQ alleles in the MSC1, MSC2, MSC3, MSC4. The genetype of STR in the MSC1, MSC2, MSC3, MSC4 was different. MSC 3 was examined by TP-ELISA to confirm the infectious disease of TP. MSC2 was contaminated by mycoplasma at passage 5. It is concluded that culture expansion causes MSCs to gradually lose their stem cell properties. During ex-vivo expansion of MSCs, the osteogenic differentiation potential is decreased. MSCs before passage 8 can be a valuable subject for basic research and clinical application.