Micronucleus induction after whole-body microwave irradiation of rats.

Adult male Wistar rats were exposed for 2 h a day, 7 days a week for up to 30 days to continuous 2,450 MHz radiofrequency microwave (rf/MW) radiation at a power density of 5-10 mW/cm(2). Sham-exposed rats were used as controls. After ether anesthesia, experimental animals were euthanized on the final irradiation day for each treated group. Peripheral blood smears were examined for the extent of genotoxicity, as indicated by the presence of micronuclei in polychromatic erythrocytes (PCEs). The results for the time-course of PCEs indicated significant differences (P<0.05) for the 2nd, the 8th and the 15th day between control and treated subgroups of animals. Increased influx of immature erythrocytes into the peripheral circulation at the beginning of the experiment revealed that the proliferation and maturation of nucleated erythropoietic cells were affected by exposure to the 2,450 MHz radiofrequency radiation. Such findings are indicators of radiation effects on bone-marrow erythropoiesis and their subsequent effects in circulating red cells. The incidence of micronuclei/1,000 PCEs in peripheral blood was significantly increased (P<0.05) in the subgroup exposed to rf/MW radiation after eight irradiation treatments of 2 h each in comparison with the sham-exposed control group. It is likely that an adaptive mechanism, both in erythrocytopoiesis and genotoxicity appeared in the rat experimental model during the subchronic irradiation treatment.