The data obtained in this work demonstrate important biological effects of monochromatic microwave irradiation at 35 GHz. Low-level microwave irradiation induces chromatin condensation in human cells and damages of cell membranes.

Abstract:To investigate the influence of microwave radiation on the human fibroblast nuclei, the effects of three variants of electromagnetic wave polarization, linear and left-handed and right-handed elliptically polarized, were examined. Experimental conditions were: frequency (f) 36.65 GHz, power density (P) at the surface of exposed object 1, 10, 30, and 100 µW/cm 2 , exposure time 10 s. Human fibroblasts growing in a monolayer on a cover slide were exposed to microwave electromagnetic radiation. The layer of medium that covered cells during microwave exposure was about 1 mm thick. Cells were stained immediately after irradiation by 2% (w/v) orcein solution in 45% (w/v) acetic acid. Experiments were made at room temperature (25 °C), and control cell samples were processed in the same conditions. We assessed heterochromatin granule quantity (HGQ) at 600× magnification. Microwave irradiation at the intensity of 1 µW/cm 2 produced no effect, and irradiation at the intensities of 10 and 100 µW/cm 2 induced an increase in HGQ. More intense irradiation induced more chromatin condensation. The right-handed elliptically polarized radiation revealed more biological activity than the left-handed polarized one.

Communicated by Aleksandrs RapoportsCells of human buccal epithelium of six male donors were exposed to microwave radiation (frequency f = 36.64 GHz, power density W = 0.1, 1 and 4 W/m 2 ). Exposure time was 10 seconds. The state of chromatin in cell nucleus was estimated by a number of heterochromatin granules after staining with 2% orcein in 45 % acetic acid. Permeability of cell membranes was estimated by percentage of unstained cells after 5 min of staining the cells with vital dyes trypan blue (0.5%) and indigocarmine (5 mM). Cell exposure to microwaves induced chromatin condensation (increase of the number of heterochromatin granules) and increase of membrane permeability to trypan blue and indigocarmine. Isolated human buccal cells demonstrated the ability to recover after microwave exposure. The number of heterochromatin granules decreased to its initial level after 0.5 hour (W = 0.1 W/m2 ) and 2 hours (W = 1 and 4 W/m 2 ) after cell exposure. Cell plasma membrane permeability recovered later -after 1 hour and 3 hours post exposure, respectively. Key words: human cell, chromatin, heterochromatin, buccal epithelium, electromagnetic radiation exposure. 13Proc. Latvian Acad. Sci., Section B, Vol. 65 (2011), No. 1/2. after electromagnetic cell exposure has been shown earlier (Shckorbatov et al., 2009a;Pasiuga et al., 2009), but in this paper for the first time we test the dependence of cell recovery on the intensity of microwave exposure. MATERIALS AND METHODSHuman cells. The studies were conducted using buccal epithelium human cells. The cells were obtained from the inner surface of donor's cheek by light scraping with a blunt sterile spatula. This operation was absolutely bloodless and painless. All the donors were informed about the purpose of investigation. Our investigations were performed in accordance with the European Convention on Human Rights and Biomedicine (1997), Declarations and Recommendations of the First, the Second and the Third National (Ukrainian) Congresses of Bioethics (Kiev, Ukraine, 2001, 2004, 2007 and Ukrainian legislation.The cells were placed in a 3.03 mM phosphate buffer (pH = 7.0) and 2.89 mM calcium chloride (Reachem, Moscow, Russia) solution, and stored for further experiments. 25 µl of cell suspension containing several thousand of cells were placed on a glass slide and subjected to microwave exposure. Cells were stained immediately after the exposure, 30 minutes, 1 hour, 2 and 3 hours after cell exposure with 2% orcein (Merck AG, Darmstadt, Germany) solution in 45 % acetic acid (Reachem, Moscow, Russia), 5 mM indigocarmine (Merck AG, Darmstadt, Germany) and 0.5% trypan blue (Reachem, Moscow, Russia) solutions. All cell donors were men, non-smokers. Ages of the donors A to F, respectively, were 18, 20, 24, 35, 53, and 55 years. The male donors were selected by the reasons of convenience, as in our previous experiments no gender-related differences between buccal epithelium cells in charateristics of chromatin condensation or membrane permeability was observed. For light mic...

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