[Biological stability analysis of QY1 pluripotential mesenchymal stem cell line from Sprague Dawley rat bone marrow].

OBJECTIVE: To explore the optimal culture conditions in vitro and the biological characterizations of the QY1 pluripotential mesenchymal stem cell (MSC) line from Sprague-Dawley rat bone marrow and to analyze the biological stability of this MSC line so as to provide an ideal cell model for the further differentiation and actual application. METHODS: The methods and technologies of cell biology and stem cell tissue engineering were used to purify MSCs. We determined the effects of morphology of cell proliferation, the time of change medium, growth curves, doubling time, adhesive rates, chromosome, culture conditions, and repeated frost on the biological characterizations of MSCs. RESULTS: The cells had a fibroblastic-like morphology and were well spread out; 80% - 90% cells became confluent between 10 and 12 days in primary culture. The growth curves of Passage 1, 3, 10, and 20 were quite similar (P>0.05). The doubling time of passage 1, 3, 10, and 20 were 34.2, 33.9, 31.8, and 30.6 hours, respectively. The adhesive rates of Passage 1, 3, 10, and 20 were very much similar (P>0.05) and about 89% subcultured cells adhered to the wall in 10 hours. The most appropriate concentration of serum was 20% and the most appropriate concentration of cell number was 8 x 10(4)/mL. The cells of Passage 8 showed light red cytoplasm and heavy blue nuclear stained by Giemsa staining. The chromosomes of Passage 8 and 20 were normal in appearance and their karyotypes were 42, XY. The cells were resuscitable after repeated frozen, and more than 85% cells were alive. The cells had been continuously cultured for more than 10 months so far. CONCLUSION: The QY1 MSCs line from Sprague-Dawley rat bone marrow is a purified cell line, which can maintain its undifferentiation and the stable biological characterizations for the long term.

[Induction of committed differentiation from yolk sac stem cells to CFU-GM].

OBJECTIVE: To set up a stable technology for the growth of yolk sac CFU-GM. METHODS: The effects of various inductive factors on the growth of yolk sac CFU-GM and the characteristic of colonies were investigated. In vitro agar culture method was used in this study. RESULTS: We found close relationship between the number of E7.5 - E8.5 yolk sac cells planted and the number of the formation of CFU-GM colonies. The number of the formation of CFU-GM colonies in DMEM culture system was higher than that in the IMDM culture system with the same number of yolk sac cells planted. The effect of HS culture system on the formation of CFU-GM colonies was better than that of FBS culture system. In contrast with GM-CSF, WEHI-3-CM had much more significant CFU-GM growth promoting effect (4.14 times improved, P < 0.01). The colonies derived from yolk sac cells in this study were CFU-GM colonies by in situ fixation and H. E staining. CONCLUSION: The committed differentiation from yolk sac stem cells to CFU-GM is affected by many factors. The combination of DMEM, HS, GM-CSF or WEHI-3-CM in culture system is optimal for yolk sac CFU-GM growth.