EN
Twenty-four male Wistar rats were selected and divided into three groups (control, test group 1, test group 2). The test group 1 was exposed to EMF (50 Hz, 3 mT) 8 h a day, 6 d per week for 2 months. Test group 2 was exposed to EMF (50 Hz, 3 mT) 8 h a day, 6 d per week for 2 months but received orally 30 mg of vitamin E/d. Rats in the control group neither were exposed to electromagnetic field nor received vitamin E. At the end of the experiment, the rats were sacrificed, dissected, and samples from the thymus were taken and processed for light and electron microscopic studies. Forty microscopic fields from each group were randomly selected and studied. The data showed that in the thymus of test group 1, the population of cells in the cortex was decreased but the number of macrophages was increased. EM study showed that cellular nuclei were heterochromatic in comparison to control group. Test group 2 was similar to the control group. These findings indicate that immune system is weakened by electromagnetic field but vitamin E supplementation prevented above alteration.