Abstract:

BACKGROUND: c-kit+Lin- bone marrow derived liver stem cells are similar to other hemopoietic stem cells and not rich in bone marrow, so it is difficult to meet the needs of scientific research.
OBJECTIVE: To elucidate the effect of optimal cytokine combinations with interleukin-3 (IL-3) on the proliferation of c-kit+Lin- cells in bone marrow.
METHODS: c-kit+Lin- cells were isolated from mouse bone marrow by using a high-gradient magnetic cell sorting system (MACS), and different concentrations of IL-3 were injected into the combinations of stem cell factor (SCF), hepatic growth factor (HGF), FLt-3 ligand (FL), leukemia inhibitor factor (LIF), thrombopoietin (TPO) and cultured for 7 days in a liquid culture system. The number of cells, multiples of c-kit+Lin- cell proliferation and the apoptosis rate were detected.
RESULTS AND CONCLUSION: Each group could expand c-kit+Lin- cells rapidly, and the numbers of cells expanded were 7-19 times as large as the beginning’s number. But when the concentration of IL-3 increased and reached to a certain concentration, the c-kit+Lin- cells did not increased effectively. The expansion of total cells was 245.41 times in 40 μg/L IL-3 group, but the expansion of c-kit+Lin- cells was only 15.80 times. There was significant difference between the 40 μg/L IL-3 group and 20 μg/L IL-3 group (P < 0.05). And in the 40 μg/L IL-3 group, the apoptosis rate showed the lowest was 4.66%. IL-3 showed a stronger potential for expanding c-kit+Lin- cells. It showed synergistic actions with SCF, HGF, FL, LIF and TPO to expand c-kit+Lin- cells and the phenotype was not changed, but too much IL-3 could not increased the c-kit+Lin- cells effectively.
20 μg/L IL-3 was the best concentration to expand c-kit+Lin- cells.