Adaptive response in mice exposed to 900 MHZ radiofrequency fields: Bleomycin-induced DNA and oxidative damage/repair

Abstract

Purpose: To determine whether mice exposed to radiofrequency fields (RF) and then injected with a radiomimetic drug, bleomycin (BLM), exhibit adaptive response and provide some mechanistic evidence for such response.

Materials and methods: Adult mice were exposed to 900 MHz RF at 120 μW/cm² power density for 4 hours/day for 7 days. Immediately after the last exposure, some mice were sacrificed while the others were injected with BLM 4 h later. In each animal: (i) The primary DNA damage and BLM-induced damage as well as its repair kinetics were determined in blood leukocytes; and (ii) the oxidative damage was determined from malondialdehyde (MDA) levels and the antioxidant status was assessed from superoxide dismutase (SOD) levels in plasma, liver and lung tissues.

Results: There were no indications for increased DNA and oxidative damages in mice exposed to RF alone in contrast to those treated with BLM alone. Mice exposed to RF+ BLM showed significantly: (a) reduced BLM-induced DNA damage and that remained after each 30, 60, 90, 120 and 150 min repair time, and (b) decreased levels of MDA in plasma and liver, and increased SOD level in the lung.

Conclusions: The overall data suggested that RF exposure was capable of inducing adaptive response and mitigated BLM- induced DNA and oxidative damages by activating certain cellular processes.

Keywords::

• Radiofrequency fields
• adaptive response
• bleomycin
• mice
• DNA damage/repair
• oxidative damage/repair

Acknowledgements

We are grateful to Dr Vijayalaxmi, Department of Radiology and Dr Thomas J. Prihoda, Department of Pathology, University of Texas Health Science Centre, San Antonio, Texas, USA for their help in the preparation of the manuscript and in statistical analyses, respectively. This research is supported by funding from the National Natural Science Foundation of China (grant# 81373025, #81302463), 973 project grant from China Ministry of Science and Technology (2011CB503705) and the Priority Academic Program Development of Jiangsu Higher Education Institutions. The funding agencies had no role in designing the experiments, data collection and analysis, preparation of the manuscript, and decision to publish the results. We also thank the technicians in the laboratory for help during the experimentation.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.