电磁辐射对CD34+造血干细胞JAK2和STAT5蛋白活化的影响及意义

目的 观察电磁辐射对CD34+造血干细胞JAK2和STAT5蛋白活化的影响,探讨JAK2和STAT5蛋白在电磁辐射致造血干细胞损伤中的作用。方法 从脐血中分离培养CD34+造血干细胞,分别用平均功率为1、5、25 mW/cm²的电磁波辐射20 min,干预组(平均辐射强度为25 mW/cm²)使用AG490(终浓度10^-6 mol/L)预处理CD34+造血干细胞30 min。检测正常组、辐射组和干预组12、24和48 h时细胞活力(MTT法)、细胞凋亡率(流式细胞术)、Caspase-3蛋白水平(WB法)、磷酸化JAK2和STAT5蛋白水平(WB法)。结果 与正常组比较,辐射组细胞12和24 h活力降低、细胞凋亡率升高,具有剂量效应,磷酸化JAK2和STAT5蛋白表达呈升高后降低的趋势。干预组12和24 h细胞活力显著高于辐射25 mW/cm²组,细胞凋亡率显著低于辐射25 mW/cm²组,磷酸化JAK2和STAT5蛋白水平较辐射25 mW/cm²组低。结论 JAK2和STAT5蛋白参与了1～25 mW/cm²功率范围内的电磁辐射对CD34+造血干细胞的损伤过程,阻断JAK2和STAT5蛋白活化可缓解CD34+造血干细胞凋亡的发生。

Effect of electromagnetic exposure on activation of JAK2 and STAT5 in CD34+cord blood stem cells

Objective To observe the effect of electromagnetic radiation on the activation of JAK2 and STAT5 in the CD34+cord blood stem cell.Methods CD34+cord blood stem cells were isolated from the umbilical cord blood. Three exposed groups were administered with 1, 5, 25 mW/cm² electromagnetic exposure for 20 minutes, respectively. In the intervention group with the radiation power of 25 mW/cm², AG490 of the final concentration of 10^-6 mol/L was pretreated for 30 minutes. The cell viability (MTT), the rate of apoptosis (FCM), Caspase-3 protein level (WB) and the activation of JAK2 and STAT5 (WB) were assayed. Results Compared with the normal group, the cell viability of the electromagnetic group decreased at 12 h and 24 h, while apoptosis rate increased with dose. The activation of JAK2 and STAT5 increased at 12 h and 24 h and then decreased. The cell viability of the intervention group was significantly higher than the electromagnetic group with 25 mW/cm² irradiation at 12 h and 24 h, and apoptosis rate was significantly decreased as activation of JAK2 and STAT5 were lower. Conclusion JAK2 and STAT5 protein are involved in the process of the electromagnetic radiation within a scope of power (1-25 mW/cm²) damaging CD34+cord blood stem cells, suggesting that blocking the activation of JAK2 and STAT5 may be effective to alleviate the cell apoptosis of stem cells.