使用抗氧化剂调控胞内的ROS对脐血CD34^＋细胞体外扩增特性的影响

目的:使用抗氧化剂调控胞内活性氧物质(ROS)水平, 考察其对脐血CD34 细胞体外扩增特性的影响.方法:在体外培养过程中, 分别采用超氧化物歧化酶(SOD)、过氧化氢酶(CAT)或N-乙酰半胱氨酸(NAC)3种抗氧化剂降低脐血CD34 细胞内的ROS水平, 研究了CD34 细胞在抗氧化剂清除ROS后的体外扩增特性.结果:体外培养时细胞因子的应用会使细胞内的ROS水平显著上升.3种抗氧化剂均能有效地清除细胞内ROS, 且清除程度随使用剂量的改变而变化.在培养体系中添加2 000 U/mL SOD、 200 U/mL CAT 或2 mmol/L NAC, 扩增后培养物中CD34 细胞及CD34 CD38-细胞的比例、 集落生成细胞的密度均有明显提高, 但对CD34 细胞扩增倍数影响不大; 而加入8 000 U/mL SOD、 1 000 U/mL CAT 或5 mmol/L NAC, 抑制CD34 细胞的扩增能力.结论:采用细胞因子体外扩增脐血CD34 细胞时, 使用低剂量的抗氧化剂适度清除细胞内的ROS, 明显提高培养物中造血干/祖细胞的含量, 同时并不影响扩增后CD34 细胞的再扩增能力.

Effect of regulating intracellular ROS with antioxidants on the ex vivo expansion of cord blood CD34+cells

AIM: To investigate the effect of regulating intracellular ROS with antioxidants on the ex vivo expansion of cord blood CD34(+) cells. METHODS: The levels of reactive oxygen species (ROS) in cord blood CD34(+) cells were reduced by superoxide dismutase (SOD), catalase (CAT) or N-acetylcysteine (NAC) in ex vivo expansion. The expansion of CD34(+) cells reducing ROS levels with antioxidant was studied. RESULTS: It was observed that the generation of ROS was increased markedly by the cytokine combination. ROS was eliminated by antioxidant effectively. With the addition of antioxidant at different concentration, ROS was reduced to different levels. The percentage of CD34(+) cells and CD34(+)CD38(-) cells, the colony growth of colony-forming cells (CFC) and the re-expansion capability of CD34(+) cells were enhanced by 2 000 U/mL SOD, 200 U/mL CAT or 2 mmol/L NAC. However, its effect on fold expansion of CD34(+) cells was not significant. The expansion of the cells was inhibited by 8 000 U/mL SOD, 1 000 U/mL CAT or 5 mmol/L NAC. CONCLUSION: The proportion of hematopoietic stem and progenitor cells in the culture substance was increased markedly with the addition of low dose antioxidants in ex vivo expansion.