Stereological analysis of the adrenal gland of female rats after exposure to an electromagnetic field

Some results about the long-term effect of a low frequency electromagnetic field (LF-EMF; 50Hz) on the functional activity of the adrenal gland of female rats, strain Mill Hill, are presented in the paper. Stereological analysis of the cortex and medulla of the adrenal gland was performed using the M42 multipurpose test system (Weibel, 1979). Every tenth section of serially cut gland was measured, at the enlargement 100X and the thickness of the sections was 5 mu m. Exposure to LF-EMF caused an increase of body weight (13.59%; p <0.05) and a decrease of absolute (18.03%; p <0.05) and relative weight of the adrenal gland (13.03%; p <0.01). Stereological analysis indicated a smaller relative volume of the adrenal cortex (p <0.05) and increased the relative volume of the adrenal gland medulla (p<0.05). Clear differentiation of all zones was seen: zona glomerulosa, zona fasciculata, zona reticularis in both treated and control groups of animals. Changes in structure were clearly visible in the adrenocorticocytes of zona fasciculata and zona reticularis in treated animals. Prominent hyperemia was seen also, in the cortex as well as in the medulla of adrenal glands of the treated animals. In the medulla adrenalocytes and noradrenalocytes could be seen and between them there were exceptionally widened blood Vessels in the treated animals. These results suggest that long term exposure to LF-EMF has a biological effect on the structure of the adrenal gland of female rats within six months.