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/cm~2 electromagnetic exposure for 20 minutes,respectively.In the intervention group with the radiation power of 25 mW/cm~2,AG490 of the final concentration of 10~(-6) mol/L was pretreated for 30 minutes.The cell viabilitv (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 JA K2 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/cm~2 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/cm~2) damaging CD34 + cord blood stem cells,suggesting that blocking the activation of JA K2 and STAT5 may be effective to alleviate the cell apoptosis of stem cells. Key words: Electromagnetic radiation;  Blood stem cell;  JAK/STAT signal pathway