【Abstract】 Objective To investigate the biocharacteristics of c-kit+ human amniotic fluid-derived mesenchymal stemcells (HAFMSCs) and its capacity to differentiate into cardiomyocytes in vitro. Methods Fifty samples of human amnioticfluid were obtained from amniocenteses or voluntary termination of pregnancy and were expanded in vitro. c-kit+ HAFMSCs were sorted by flow cytometry and were recultured in the same media. c-kit+ HAFMSCs were amplified and identified, then exposed to osteogenic , adi pogenic, and myogenic media. The flow cytometry, and immunocytochemistry were used for identifying the cell phenotype, von Kossa staining for osteogenic differentiation, oil red O staining for adi pogenic differentiation, and real-time fluorescent quantitative PCR for the expressions of NKx2.5, Tbx5, GATA-4, and α-MHC genes. Results After the selection procedure, the percentage of c-kit+ HAFMSCs was 3.07% ± 1.03% of the total adherent cells. The cells expressed MSCs markers (CD29, CD44, CD73, CD90, CD105), and did not express hematopoietic stem cells markers (CD34, CD45). The cells were positive for human leukocyte antigen (HLA)-ABC, and negative for HLA-DR. They also expressed Oct-4, which characterized the undifferentiated stem cell state. The growth curves of c-kit+ HAMFSCs at passages 5, 10, and 15 were similar. Li pid droplet was observed by oil red O staining and calcium deposition by von Kossa staining in the cells at 21 days after adi pogenic and osteogenic induction. The myocardium special gene expressions of Tbx5, Nkx2.5, GATA-4, and α-MHC were significantly ber after myogenic induction than those before myogenic induction (P lt; 0.05). Conclusion Selected c-kit+ HAFMSCs by flow cytometry is a group of pure MSCs, which has potential to differentiate into cardiomyocytes and can be used as seeding cells for myocardium regeneration treatment.
【Abstract】 Objective To isolate and culture human amniotic fluid-derived mesenchymal stem cells (HAFMSCs),to investigate a better cryopreservation protocol of HAFMSCs and to observe the biocharacteristics and the multi-potential of HAFMSCs after cryopreservation for the further fundamental researches and cl inical appl ications. Methods HAFMSCswere isolated from the amniotic fluid of pregnant women during the second trimester by the improved two-step method.HAFMSCs were cryopreserved with different cryopreservation protocols (containing different contents of FBS and DMSO atcryoprotectant) in l iquid nitrogen for 12 weeks. The biocharacteristics of the HAFMSCs after cryopreservation were analyzed. The growth characteristics were observed by MTT method and the growth curves were drawn. The surface antigens of HAFMSCs were detected using flow cytometry, including CD29, CD34, CD44, CD45, CD73, and CD90. The adi pogenic and osteogenic differentiation abil ities of HAFMSCs were observed. The mRNA levels of Oct-4 and Nanog of the HAFMSCs were compared between before and after cryopreservations. Results At 12 weeks after cryopreservation, different protocols had different effects on the cell viabil ity; the better formula of cryoprotectant was 50% DMEM, 40% FBS, and 10% DMSO. After cryopreservation, the cells proliferated rapidly and the growth curves showed “S” shape, which was the same as the cells before cryopreservation. Phenotype showed that HAFMSCs were positive for the surface markers CD29, CD44, CD73, and CD90, and negative for CD34 and CD45. After 21 days of adi pogenic differentiation, the l ipid droplets were observed by oil red O staining. After 21 days of osteogenic differentiation, the calcium mineralizations were verified by von Kossa staining. There was no significant difference (P gt; 0.05) in the mRNA levels of Oct-4 and Nanog between before and after cryopreservations. Conclusion HAFMSCs have rapid proliferation and multi-potential in vitro. The cells have high viabil ities and no changes of the biocharacteristics and differentiation potential ities after cryopreservation for 12 weeks. Cryoprotectant containing 50% DMEM, 40% FBS, and 10% DMSO is a better cryopreservation protocol.