紫外线在低氧条件下对急性早幼粒白血病细胞增殖的影响及机制研究

Effect of ultraviolet irradiation on the proliferation of acute promyelocytic leukemia cells under hypoxic conditions and related mechanisms

摘要:

目的 观察280 nm波长紫外发光二极管照射在低氧条件下对急性早幼粒白血病细胞（HL-60）增殖的影响，并探讨发生机制。方法 取对数生长期的HL-60细胞为研究对象，分为对照组、低氧组、紫外线组及低氧+紫外线组。低氧组给予氯化钴（终浓度150 μmol/L）处理，紫外线组用30 J/m²能量的280 nm波长紫外发光二极管照射，低氧+紫外线组在氯化钴处理基础上用30 J/m²能量的280 nm波长紫外发光二极管照射，48 h后收集细胞于倒置显微镜下观察细胞形态变化。采用CCK-8法检测细胞增殖抑制率；Annexin-FITC/PI双染流式细胞术检测细胞凋亡；实时荧光定量PCR检测Bcl-2基因mRNA的表达量。上述各实验均独立重复3次。结果 与对照组相比，各实验组细胞皱缩、透亮度降低、排列紊乱，随着培养时间延长，细胞数量减少。各组细胞增殖抑制率及细胞凋亡率比较差异有统计学意义（P < 0.01），其中低氧组+紫外线组细胞增殖抑制及诱导细胞凋亡作用最强，紫外线组次之，低氧组最弱。与对照组比较，低氧组、紫外线组及低氧+紫外线组Bcl-2 mRNA的表达逐渐下调，且低氧+紫外线组Bcl-2 mRNA表达量较低氧组和紫外线组下调更明显（P < 0.05）。结论 低氧和紫外线作用均可抑制HL-60细胞增殖，诱导细胞凋亡，紫外线在低氧条件下对细胞的增殖抑制及凋亡作用较常氧条件下更明显，其机制可能与Bcl-2基因表达下调有关。

Abstract:

Objective To study the effect of 280 nm-LED ultraviolet irradiation on the proliferation of acute promyelocytic leukemia (APL) HL-60 cells under hypoxic conditions and related mechanism. Methods HL-60 cells in the logarithmic growth phase were selected and divided into control, hypoxia, ultraviolet and hypoxia+ultraviolet groups. The cells in the hypoxia group were treated with cobalt chloride (with a final concentration of 150 μmol/L), those in the ultraviolet group were irradiated by 280 nm-LED ultraviolet with an energy intensity of 30 J/m², and those in the hypoxia+ultraviolet group were treated with cobalt chloride and then irradiated by 280 nm-LED ultraviolet. After 48 hours of treatment, the cells were placed under an invert microscope to observe cell morphology. CCK-8 assay was used to measure the inhibition rate of cell proliferation. Annexin V-FITC/PI double staining flow cytometry was used to evaluate cell apoptosis. Quantitative real-time PCR was used to measure the mRNA expression of Bcl-2. Each experiment above was repeated three times independently. Results Compared with the control group, the experimental groups showed shrinkage, decreased brightness, and disordered arrangement of cells, and the number of cells decreased over the time of culture. There were significant differences in the inhibition rate of cell proliferation and cell apoptosis rate among the groups (P < 0.01), and the hypoxia+ultraviolet group showed the strongest inhibition of cell proliferation and induction of cell apoptosis, followed by the ultraviolet group and the hypoxia group. Compared with the control group, the other three groups had a gradual reduction in the mRNA expression of Bcl-2, and the hypoxia+ultraviolet group had a significantly greater reduction than the hypoxia and ultraviolet groups (P < 0.01). Conclusions Both hypoxia and ultraviolet irradiation can inhibit the proliferation of HL-60 cells and induce cell apoptosis, and ultraviolet irradiation has a better effect on proliferation inhibition and cell apoptosis under hypoxic conditions than under normoxic conditions, possibly by downregulating the mRNA expression of Bcl-2.