Protective effect of melatonin on thymus of rats exposed to microwave radiation Branka Djordjevic, Dusan Sokolovic, Andrej Veljkovic, Milena Marinkovic, Jelena Basic , Gordana Kocic, Jelenka Nikolic Department of Biochemistry, Faculty of Medicine, University of Nis. Bul. dr Zorana Djindjica 81, 18000 Nis, Serbia

Microwaves 300 GHz - 300 MHz 1mm-1m 1.24 µeV - 1.24 meV

Microwaves and oxidative stress

“Thymus plays an important role in the immune system development...” Matsui N, Nitta T, Takahama Y. Development of the thymus and immune system. Brain Nerve 2011;63(7):679-84. “...which can be modulated by numerous environmental factors, including MWs.” Quaglino D, Capri M, Ronchetti IP. Modulation of cell death in the rat thymus. Light and electron microscopic investigations. Ann N Y Acad Sci 2000;926:79-82. “Oxidative stress has been implicated in thymus disorders.“ Yan M, Shen J, Person MD, Kuang X, Lynn WS, Atlas D, et al. Endoplasmic reticulum stress and unfolded protein response in Atm-deficient thymocytes and thymic lymphoma cells are attributable to oxidative stress. Neoplasia. 2008;10(2):160-7.

MWs have already been linked to cancer, especially childhood leukemia and T cell non Hodgkin lymphoma. Myung SK, Ju W, McDonnell DD, Lee YJ, Kazinets G, Cheng CT, et al. Mobile phone use and risk of tumors: a meta-analysis. J Clin Oncol 2009;27(33):5565-72. Lowenthal RM, Tuck DM, Bray IC. Residential exposure to electric power transmission lines and risk of lymphoproliferative and myeloproliferative disorders: a case-control study. Intern Med J 2007; 37(9):614-9.

Melatonin (N-acetyl-5-methoxytryptamine) sinthetised and released from pineal gland MT1 and MT2 receptors expressed in all lymphocyte subpopulations immunostimulant and a powerfull antioxidant directly neutralizes free radicals stimulates antioxidant enzyme activity prevents oxidative injury of DNA molecules inhibits apoptosis in immune cells

Aim of the study The present study was designed to evaluate the effects of MWs on oxidative stress parametars in the thymus tissue and to clarify if melatonin treatment may favorably impact on thymus tissue injury in rats exposed to microwave radiation.

Experimental setup 3-week daily administration of melatonin (2 mg/kg i.p.) adult Wistar rats exposition to microwaves (4 hours/day) Wistar rats were divided in four groups: I (control) - rats treated with saline, II (Mel) - rats treated with melatonin, III (MWs) - microwave exposed rats, IV (MWs + Mel) - MWs exposed rats treated with melatonin.

Exposure system plastic cage mobile phone (NOKIA 3110 classic, Nokia Mobile Phones Ltd.) 900 MHz electromagnetic near field continuous wave AARONIA SPECTRAN HF6080 EMF meter SAR 0.089 W/kg (0.043-0.135 W/kg)

Biochemical analysis Malondialdehyde (MDA) Protein carbonyls Thymus tissue was prepared as 10% homogenate. Malondialdehyde (MDA) Protein carbonyls Catalase (CAT) Xantine oxidase (XO) Proteins

MDA *** (p < 0.001) + (p < 0.05) Ohkawa H, OhishiN, Yagi K. Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction. Anal Biochem 1979;95(2):351-8.

Protein carbonyls *** (p < 0.001) +++ (p < 0.001) Levine RL, WIilliams JA, Stadtman ER, et al. Carbonyl assay for determination of oxidatively modified proteins. Methods Enzymol 1994;233:346-57.

Catalase *** (p < 0.001) +++ (p < 0.001) Goth L . A simple method for determination of serum catalase activity and revision of reference range. Clin Chim Acta 1991;196(2-3):143-51.

Xantine oxidase *** (p < 0.001) +++ (p < 0.001) Hashimoto S. A new spectrophotometric assay method of xanthine oxidase in crude tissue homogenate. Anal Biochem 1974;62(2):426-35.

Conclusion Melatonin exerts potent antioxidant effects in thymus of rats exposed to microwaves.

Thank you very much for your kind attention! This work was supported by the Ministry of Education and Science of Republic Serbia (Project 43012). Thank you very much for your kind attention! Branka Djordjevic, Dusan Sokolovic, Andrej Veljkovic, Milena Marinkovic, Jelena Basic , Gordana Kocic, Jelenka Nikolic Department of Biochemistry, Faculty of Medicine, University of Nis.