Human cell recovery after microwave irradiation

Cells of human buccal epithelium of 6 male donors were exposed to microwave radiation (frequency f=36,64 GHz, power density E=10, 100, and 400 µW/cm 2). Exposure time in all experiments was 10 seconds. Heterochromatin was stained by 2% orcein in 45 % acetic acid. The stainability of cells with trypan blue (0,5 %) and indigocarmine (5 mM) after 5 min of staining was investigated. Irradiation induced chromatin condensation (increase of number of heterochromatin granules) and increase of membrane permeability to vital dyes trypan blue and indigocarmine. Isolated human buccal cells had shown the ability to recover these changes. Number of heterochromatin granules lowered to initial level after 0,5 hour (E=10 µW/cm 2) and 2 hours (E=100, and 400 µW/cm 2) after irradiation. Cell plasma membrane permeability recovered a bit later, in correspondence, after 1 hour and 3 hours after irradiation.