Studies on the Effect of Electromagnetic Field Exposure on Experimental Animals

Abstract

Abstract The study was planned to evaluate the effect of two different electromagnetic fields (EMF) on experimental animals at different exposure levels. In the first experiment, the mice were exposed to isothermal non-ionizing EMF, represented by the man-made visible light (artificial visible light of intensity of 77 mW/cmz on the area of 72.5 cmz and frequency of EM radiation within (3.9x1Ol4 Hz and 7.5x10'4 Hz W/cmz) 8 hours per day for 3, 6 and 12 days respectively . In the second experiment, mice were exposed to lmT magnetic field (MF) (12 hours/day) for 15, 30 or 60 days. The present used strengths were chosen because they are almost similar to the level of human exposure. The first experiment showed that exposure of mice to visible light caused time-dependent dramatic histological alterations of the testis and pituitary glands. Exposure caused severe degenerative effects on the testes histological architecture, size and reduction in the seminiferous tubules‘ diameters. Transmission electron microscopy (TEM) clarified that the degenerative effects were evident in all germ and Sertoli cells. In the pituitary glands, visible light caused degenerative effects in the gonad trope cells, mild to moderate hemorrhage after 3 and 6 days of treatment, and severe hemorrhage and shrinkage of most pituitary gland secretary cells after 12 days. Serum biochemical analysis of testosterone, follicular stimulating hormone (FSH), luteinizing hormone (LH) and the hypothalamus Gonad tropic releasing hormone (GnRH) that stimulates the pituitary gland regulation of testicular testosterone through the FSH and LH hormones were allfound to be time-dependent and significantly decreased by exposure particularly after 12 days. Visible light did not affect the serum total protein levels, aspartate aminotrausferase (AST) activity, alanine aminotransferase (ALT) activity or growth hormone (GI-I) levels. DNA ploidy analysis revealed no carcinogenic effect on the pituitary glands, however it revealed significant down regulation of the proliferative activity of the cells after 12 days. On the other hand, the results of experiment (2) showed no histopathological effects of type of magnetic field on any organ of the mice. The results indicate that man-made visible light but not static magnetic field may affect the endocrine homeostasis of mice by exerting histopathological changes in the pituitary glands cells that may subsequently cause a harmful effect on the testis through reducing the gonad tropic hormones activities that regulates testicular spermato genesis and integrity