目的　研究辐射所致造血功能障碍时造血干 祖细胞表面CD34抗原表达的变化及其意义。方法　采用逆转录聚合酶链反应 (RT PCR)及斑点杂交的方法 ,初步检测了昆明种小鼠受 6 0Gy辐照后不同时相点时骨髓单个核细胞CD34表达量的变化 ,并对其可能的机理及其临床意义进行了探讨。结果　放射损伤后小鼠骨髓单个核细胞CD34表达在受照后 2 4h即明显增高 ,之后一直维持在较高水平 ,至照后 15d时仍较正常时高 5 0 %。结论　在此照射剂量时小鼠骨髓内残存的、具有造血功能的早期造血祖细胞在骨髓造血的内稳态遭到破坏后 ,可代偿性地迅速增加其增殖能力和细胞数量 ,以加速造血的恢复过程。这可能是机体对损伤导致造血功能低下时的一种代偿性增生机理 Objective To study the changes and significance of CD34 antigen expression on hematopoietic stem / progenitor cells when hematopoietic dysfunction caused by radiation. Methods The expression of CD34 in bone marrow mononuclear cells from Kunming mice irradiated with 60 Gy was detected by RT-PCR and dot-blot hybridization. The mechanism and clinical significance are discussed. Results The expression of CD34 in bone marrow mononuclear cells of irradiated mice was significantly increased at 24 hours after irradiation and maintained at a relatively high level until 50 days after irradiation. Conclusions The hematopoietic progenitor cells that remain in the bone marrow of mice at this irradiation dose can rapidly increase their proliferative capacity and cell number in a compensatory manner after the homeostasis of bone marrow hematopoiesis has been destroyed, Recovery process. This may be a compensatory mechanism of hyperproliferation when the body causes damage to hematopoietic function