Investigation on the effects of Melatonin on the thyroid gland in pregnant and infant rats subjects to electromagnetic radiation

Investigation on the Effects of Melatonin on the Thyroid Gland in Pregnant and Infant Rats Subjects to Electromagnetic Radiation.In this study, we investigated protective effect of melatonin on thyroid glands in pregnancy period and infant rats subjects to 50 Hz frequents electromagnetic radiation that is frequently encounter in daily life. After monitoring estrous cycle the rats were mated and tested for gestation then 28 Wistar pregnant rats randomly selected and put into 4 groups (each group n = 7 ): Group I control, Group II sham (keeping rats in EMF apparatus for 4 hours without any exposure to EMF + Melatonin ), Group III EMF exposed and group IV EMF exposed + Melatonin. The EMF exposed and sham groups (II and IV groups) had intraperitoneal singe dose of a 4 mg/kg melatonin (0.1 ml/100 g) at 10:00 o?clock daily up to the end of gestation. For EMF exposed and control groups had daily intraperitoneal injections of physiologic saline (0.1 ml/100 g) containing 5% ethanol. After birth of rats, mother rats and their infants of thyroid tissues were submitted for histological examination under light microscopy by ımmunohistochem (TUNEL ve Caspase 3), H&E, Mallory anilin Blue, PAS staining methods and morphometric assays. Also ultrastructural changes were assessed by transmission electron microscope. According to immunohistochem examinations (TUNEL and Caspase 3) in EMF exposed animals were observed cellular damage and apoptosis. Histopathological and morphometric analysis showed a significantly increased number cellular damage and apoptotic cells, decreased diameter assay of thyroid follicles, decreased intrafollicular colloid content in lumen, increased volume of interfollicular connective tissue and in EMF exposed animals compared to EMF exposed + Melatonin, control and sham non-exposed groups. Ultrastructural analysis of thyroid follicular cells in the EMF exposed group showed alterations in mitochondria as slender form, dilatation of granular endoplasmic reticulum, numerous apical lysosomes, finds of several colloid droplets dentate form of cell nuclei with incisions and a higher density of heterochromatin compared to the other groups were also observed. There were statistically significant differences between EMF exposed animals compared to EMF exposed + Melatonin animals groups. Finally results demonstrate that melatonin antioxidant benefits may have a preventive effect against EMF exposed injury on thyroid glands.Key words: Electromagnetic Fields, Thyroid gland, Melatonin, Immunohistochemistry