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Volume 4, Pages 91-99
Research Article

The Effect on Rat Thymocytes of the Simultaneous In Vivo Exposure to 50-Hz Electric and Magnetic Field and to Continuous Light

1Department of Biomedical Sciences-General Pathology, University of Modena and Reggio Emilia, Via Campi 287, 4100 Modena, Italy
2Department of Experimental Pathology, University of Bologna, Via San Giacomo 14, 40126 Bologna, Italy
3Interdepartment Center L. Galvani, University of Bologna, Via S. Giacomo 12, 40126 Bologna, Italy
4Institute of Advanced Biomedical Technologies-CNR, Segrate, Milano, Italy

Received 26 July 2004; Revised 30 August 2004; Accepted 30 August 2004

Copyright © 2004 Daniela Quaglino et al.


Thymus plays an important role in the immune system and can be modulated by numerous environmental factors, including electromagnetic fields (EMF). The present study has been undertaken with the aim to investigate the role of long-term exposure to extremely low frequency electric and magnetic fields (ELF-EMF) on thymocytes of rats housed in a regular dark/light cycle or under continuous light. Male Sprague-Dawley rats, 2 months old, were exposed or sham exposed for 8 months to 50-Hz sinusoidal EMF at two levels of field strength (1 kV/m, 5 μT and 5 kV/m, 100 μT, respectively). Thymus from adult animals exhibits signs of gradual atrophy mainly due to collagen deposition and fat substitution. This physiological involution may be accelerated by continuous light exposure that induces a massive death of thymocytes. The concurrent exposure to continuous light and to ELF-EMF did not change significantly the rate of mitoses compared to sham-exposed rats, whereas the amount of cell death was significantly increased, also in comparison with animals exposed to EMF in a 12-h dark-light cycle. In conclusion, long-term exposure to ELF-EMF, in animals housed under continuous light, may reinforce the alterations due to a photic stress, suggesting that, in vivo, stress and ELF-EMF exposure can act in synergy determining a more rapid involution of the thymus and might be responsible for an increased susceptibility to the potentially hazardous effects of ELF-EMF.