不同氧浓度培养对小鼠骨髓造血干细胞生物活性的影响

本研究模拟人外周血造血干细胞(HSC)移植中HSC所经历的氧环境,研究不同氧浓度对小鼠骨髓HSC生物功能的影响及可能机制。采用体外扩增实验、定向分化实验、细胞周期分析、活性氧测定及亚致死量射线照射小鼠骨髓原始Lin-c-kit+Sca-1+HSC移植等方法,分别检测了Lin-c-kit+Sca-1+HSC的扩增能力,细胞周期,活性氧水平及造血重建能力。结果表明:低于常氧浓度,特别是乏氧的氧环境能降低活性氧的产生,增强原始骨髓HSC体外扩增能力,增加红系集落(BFU-E)、粒单集落(CFU-GM)、红系粒单系巨核系集落(CFU-GEMM)的数量,维持较多的HSC处于G0/G1期,进而明显促进移植后小鼠的脾集落(CFU-S)生长及提高移植小鼠存活数量。而暴露于常氧、不恒定且氧浓度变化剧烈的氧环境中的骨髓HSC能产生较高水平的活性氧,上述功能指标都较低。结论:骨髓HSC的活性氧水平与周围氧环境中氧浓度水平及稳定性密切相关,高水平的活性氧损害骨髓HSC的功能。在恒定的较低浓度的氧环境下培养及应用抗氧化剂对于骨髓HSC移植可能更有益。

Effect of Different Oxygen Concentrations on Biological Properties of Bone Marrow Hematopoietic Stem Cells of Mice

This study purposed to investigate the effects of different oxygen concentrations and reactive oxygen species（ROS） on the biological characteristics of hematopoietic stem cells（HSC） and their possible mechanisms through simulating oxygen environment to which the peripheral blood HSC are subjected in peripheral blood HSCT.The proliferation ability,cell cycle,directed differentiation ability,ROS level and hematopoietis reconstitution ability of Lin-c-kit＋Sca-1＋ BMHSC were detected by using in vitro amplification test,directional differentiation test,cell cycle analysis,ROS assay and transplantation of Lin-c-kit＋Sca-1＋ HSC from sublethally irradiated mice respectively.The results showed that oxygen concentrations lower than normal oxygen concentration,especially in hypoxic oxygen environment,could reduce ROS generation and amplify more primitive CD34＋AC133＋ HSC and active CD34＋ HSC,and maintain more stem cells in the G0/G1 phase,which is more helpful to the growth of CFU-S and viability of mice.At the same time,BMHSC exposed to normal oxygen level or inconstant and greatly changed oxygen concentrations could produce a high level of ROS,and the above-mentioned features and functional indicators are relatively low.It is concluded that ROS levels of HSC in BMHSCT are closely related with the oxygen concentration surrounding the cells and its stability.Low oxygen concentration and antioxidant intervention are helpful to transplantation of BMHSC.