铁过载对骨髓损伤小鼠造血功能的作用及机制研究

Effects and mechanism of iron overload on hematopoiesis in mice with bone marrow injury

目的 探讨铁过载对骨髓损伤小鼠造血功能的作用及可能机制.方法 将20只C57BL/6雄性小鼠随机分为对照组、铁剂组、照射组、照射＋铁剂组,每组5只.通过给予小鼠4Gyγ射线照射及腹腔注射右旋糖酐铁建立骨髓损伤小鼠铁过载模型,观察各组小鼠铁负荷情况及骨髓单个核细胞（BMMNC）内可变铁池水平,检测各组小鼠外周血常规的改变;检测BMMNC数,红系、粒-单核系细胞比例及造血干/祖细胞功能改变;分析骨髓细胞,红系和粒-单核系细胞活性氧物质（ROS）水平.结果 ①骨髓活检及流式细胞术检测均显示发生铁过载.②与对照组相比,照射组小鼠血小板计数显著降低[（801.9±81.2）×10^9/L对（926.0±28.2）×10^9/L],BMMNC数及红系、粒-单核系细胞比例明显降低,骨髓造血集落形成单位（CFU）数和造血干细胞单克隆培养数明显减少（P值均＜0.05）.③与照射组相比,照射＋铁剂组小鼠血小板计数显著降低[（619.0±60.9）×10^9/L对（801.9±81.2）×10^9/L],红系、粒-单核系细胞比例明显降低,骨髓造血CFU数和造血干细胞单克隆形成数明显减少（P值均＜0.05）.④照射＋铁剂组BMMNC、红系和粒-单核系细胞ROS水平较照射组分别升高1.94、1.93和2.70倍（P值均＜ 0.05）.结论 4Gyγ射线照射可造成小鼠骨髓损伤,在骨髓损伤基础上发生铁过载会加重损伤造血干/祖细胞功能,进一步研究发现可能由铁过载引起BMMNC内ROS水平升高所致.

Objective To explore effects of iron overload on hematopoiesis in mice with bone marrow injury and its possible mechanism（s）.Methods C57BL/6 mice were divided into control,iron,irradiation,irradiation＋iron groups.The iron-overloaded model of bone marrow injury was set up after mice were exposed to the dose of 4 Gy total body irradiation and （or） were injected iron dextran intraperitoneally.Iron overload was confirmed by observing iron deposits in mice and bone marrow labile iron pool.Additionally,the number of peripheral blood and bone marrow mononuclear cells and the frequency of erythroid cells and myeloid cells were counted and hematopoietic function was assessed.Results ①Iron overload occurred by bone marrow biopsy and flow cytometry analysis.②Compared with control group,the number ofplatelets [（801.9±81.2） × 10^9/L vs （926.0±28.2） × 10^9/L] and BMMNC and the frequency of erythroid cells and myeloid cells decreased.Moreover,hematopoietic colony forming units and single-cell cloning counts decreased significantly in irradiation group （P 〈 0.05）.③Compared with irradiation group,the number of platelets [（619.0±60.9） × 10^9/L vs （801.9±81.2） × 10^9/L] and the frequency of erythroid cells and myeloid cells decreased; moreover,hematopoietic colony forming units and singlecell cloning counts decreased significantly in irradiation ＋ iron group （P〈0.05）.④Compared with irradiation group,ROS level increased by 1.94 fold in BMMNC,1.93 fold in erythroid cells and 2.70 fold in myeloid cells,respectively （P 〈 0.05）.Conclusions The dose of 4 Gy total body irradiation caused bone marrow damage and iron overload based on this injury model,which could damage bone marrow hematopoietic function aggravatingly.And further study found that iron overload was closely related to increased ROS level in BMMNC.The findings would be helpful to further study the injury mechanism of iron overload on the hematopoiesis of bone marrow.