Effects Of 900 MHz Microwave Radiation On The Expression Of ATM/NF-?B In Mouse Bone Marrow Stromal Cells

Objective:To investigate the effects of 900 MHz microwave radiation on the expression of ATM/NF-?B in mouse bone marrow stromal cells via ROS production.Methods:1.The role of ROS in activation of ATM and NF-?B induced by 900 MHz microwave radiation.Mouse bone marrow stromal cells(BMSCs)prepared using the method established in our laboratory were randomly divided into the following groups:(1)control group(without any treatment),(2)RF group(120?W/cm2 900 MHz microwave irradiation,4h/day,for 5 days),(3)sham group(cells were exposed in microwave exposure system,but without microwave exposure,4h/day,for 5 days),(4)?-rays group(cells were subjected to 2.0 Gy ?-rays radiation),(5)melatonin group(cells were treated with 500 n M melatonin for 4 hours),(6)melatonin+RF group(cells were pretreated with 500 n M melatonin for 4 hours,then exposed to microwave radiation,4h/day,for 5 days),(7)melatonin+sham group(cells were pretreated with 500 n M melatonin for 4 hours,then exposed in microwave exposure system but without microwave exposure,4h/day,for 5 days),(8)melatonin+?-rays group(cells were pretreated with 500 n M melatonin for 4 hours,then subjected to 2.0 Gy ?-rays radiation).Cells were collected at different post-exposure times,viz.30 minutes,2 hours and 24 hours.The level of ROS was measured by flow cytometry,the expression of ATM m RNA was measured by RT-PCR and the expression of NF-?B protein in the cytoplasm and nucleus were measured by western blot.2.The role of ATM in activation of NF-?B induced by 900 MHz microwave radiation.Mouse BMSCs were subcultured and randomly divided into the following groups:(1)control group(without any treatment),(2)RF group(120?W/cm2 900 MHz microwave irradiation,4h/day,for 5 days),(3)sham group(cells were exposed in microwave exposure system,but without microwave exposure,4h/day,for 5 days),(4)?-rays group(cells were subjected to 2.0 Gy ?-rays radiation),(5)KU55933 group(cells were treated with 10 ?M KU55933 for 1 hour),(6)KU55933+RF group(cells were pretreated with 10 ?M KU55933 for 1 hour then exposed to microwave radiation,4h/day,for 5 days),(7)KU55933+sham group(cells were pretreated with 10 ?M KU55933 for 1 hour,then exposed in microwave exposure system,but without microwave exposure,4h/day,for 5 days),(8)KU55933+?-rays group(cells were pretreated with 10 ?M KU55933 for 1 hour,then subjected to 2.0 Gy ?-rays radiation).Cells were collected at different post-exposure times,viz.30 minutes,2 hours and 24 hours.The expression of ATM m RNA was measured by RT-PCR and the expression of NF-?B protein in the cytoplasm and nucleus were measured by western blot.3.Apoptosis and cell cycle changes induced by low-dose microwave irradiation through activation of NF-?B.Mouse BMSCs were randomly divided into the following groups:(1)control group(without any treatment),(2)RF group(120?W/cm2 900 MHz microwave irradiation,4h/day,for 5 days),(3)sham group(cells were exposed in microwave exposure system,but without microwave exposure,4h/day,for 5 days),(4)?-rays group(cells were subjected to 2.0 Gy ?-rays radiation),(5)BAY 11-7082 group(cells were treated with 10 ?M BAY 11-7082 for 1.5 hours),(6)BAY 11-7082+RF group(cells were pretreated with 10 ?M BAY 11-7082 for 1.5 hours,then exposed to microwave radiation,4h/day,for 5 days),(7)BAY 11-7082+sham group(cells were pretreated with 10 ?M BAY 11-7082 for 1.5 hours,then exposed in microwave exposure system,but without microwave exposure,4h/day,for 5 days),(8)BAY 11-7082+?-rays group(cells were pretreated with 10 ?M BAY 11-7082 for 1.5 hours,then subjected to 2.0 Gy ?-rays radiation).Cells were collected at different post-exposure times,viz.30 minutes,2 hours and 24 hours.The expression of NF-?B protein in cytoplasm and nucleus and the levels of proteins associated with cell apoptosis and cell cycle were measured by western blot.Results:1.Compared with control group,30 minutes and 2 hours after microwave radiation exposure,the ROS level and the expression of ATM m RNA in cells of RF group increased significantly(P<0.05),and the expression level of nuclear NF-?B protein increased significantly while cytoplasmic NF-?B protein decreased significantly(P<0.05).Additional treatment to the cells with melatonin reversed the effects observed in cells exposed to RF alone.2.Compared with cells in control group,30 minutes and 2 hours after microwave radiation exposure,the expression level of ATM m RNA in cells of RF group increased significantly(P<0.05),and the expression level of NF-?B protein in nucleus increased significantly while NF-?B protein in cytoplasm decreased significantly(P<0.05).Additional treatment to the cells with KU55933 reversed the effects observed in cells exposed to RF alone.3.Compared with cells in control group,the expression of cytoplasmic NF-?B protein level in cells of RF group decreased while nuclear NF-?B protein level increased significantly(P<0.05)30 minutes and 2 hours after microwave radiation exposure,the expression of Bax and Cyclin D1 increased significantly and the expression of Bcl-2 and Cyclin B1 decreased significantly(P<0.05)24 hours after microwave radiation exposure.Additional treatment to the cells with BAY 11-7082 reversed the effects observed in cells exposed to RF alone.Conclusions:1.900 MHz microwave radiation could activate expression of ATM and NF-?B via ROS production.2.900 MHz microwave radiation could induce cell apoptosis and block the cell cycle through NF-?B activation.