The thermal effect of 2.45 GHz microwave radiation on rat testes

The study focused on the effect of microwave radiation at a dose which commonly does not lead to tissue heating, however, in the rat testes it resulted in accumulation of heat. Adult rats were exposed to whole body pulse radiation at a frequency of 2.45 GHz and mean power density of 28 W/m2, for 3 h a day for the duration of 3 weeks. Immediately after each irradiation, the body temperature and the testicular temperature were measured in the control and experimental animals. Samples for histological and immunohistochemical analysis were taken after the last irradiation and processed for light and transmission electron microscopy. An evaluation of spermatozoa motility was performed using computer-assisted sperm analysis. Although the body temperature of the rats was not elevated after the irradiations, the testicular temperature was significantly increased (P < 0.004). Testes of the experimental animals had considerably dilated and congested blood vessels and the seminiferous epithelium showed degenerative changes. The Leydig cells showed no obvious structural abnormalities. Transmission electron microscopy revealed ultrastructural changes in developing sex cells, Sertoli cells, and endothelial cells. An intensified immunoreactivity to superoxide dismutase 1 was found in spermatogonia and Leydig cells in the experimental animals. Results of the present study revealed a distinctly adverse effect of microwave radiation on the thermoregulatory capability and histological structure of rat testes as well as an oxidative damage of the tissue. The scientific knowledge confirming or denying the thermal effect of microwave radiation on living tissue is scarce and thus the present study may be regarded as unique and helpful to clarify the issue