[Comparison of Effect of Serum-Free Culture Systems on Directional Erythroid Differentiation of Human Umbilical Cord Blood CD34 Cells].

Objective: To compare the efficacy of directional erythroid differentiation in different serum free culture systems and to screen the optimal culture systems for inducing the differentiation of umbilical cord blood hematopoietic stem and progenior cells (HSPC) to erythroid cells.

Methods: The CD34 cells from umbilical blood munonuclear cells were sorted by using the magnetic beads, and were inoculated into 3 different of culture systems (system 1, 2 and 3 respectively), to induce erythrold differentiation by 3 stage culture. The living cells were counted in different differentiation stages and were observed by Wright-Giemsa staining; the expression of CD71 and CD235a on cell surface was detected by flow cytometry, the erythroid differentiation pteency was detected via colony-forming test.

Results: The ability of system 2 to promote the HSPC proliferation was the strongest, the efficacy of system 3 to promote the erythroid differentiation of HSPC was the most optimal; the proliferation ability of cells cultured in system 2 for 2-15 days all was higher than that of cells cutured in system 1 and 3 (P＜0.05). The flow cytometry detection showed that the expression of CD71 and CD235a on surface of cells cultured in system 3 was the highest, the CD235a percentage on day 15 of differentiation in system 3 was (92.33±3.89)%, that in system 2 was (84.67±3.12)%, while that in system 1 was (72.17±6.83)% (P＜0.05). Cell morplologic detection showed that throid differentiation was accelerated on day 12, the percentage of orthochromatic erythrocytes in system 3 was (67.67±2.08)% which was 10.69 and 25.34 times higher than that in system 2 and 1 respectively (P＜0.05). The colony-forming test showed the ratio of BFU-E in system 3 increased gradually on day 3-9 (r=0.99, P＜0.05), which was significanlly higher than that in system 2 and 1 on day 9 (90.35±5.52% vs 77.06±2.26% and 74.50±3.95%).

Conclusion: Culture system 3 is the most effective serum-free erythroid differentiation system, and the culture system 2 is the most powerful HSPC proliferation system. This study results provide a technical basis for further efficiently increasing and inducing the erythroid proliferation and differentiation of HSPC, and also provide culture system in vitro for the clinical application and basic research.