Medical/biological study (experimental study)

Induction of adaptive response in mice exposed to 900MHz radiofrequency fields: application of micronucleus assay med./bio.

By: Jiang B, Zong C, Zhao H, Ji Y, Tong J, Cao Y

Published in: Mutat Res Genet Toxicol Environ Mutagen 2013; 751 (2): 127-129

Aim of study (acc. to author)

To evaluate the extent of a DNA damage in peripheral blood erythrocytes in mice pre-exposed to 900 MHz radiofrequency (as adaptive dose) and then subjected to 3 Gy gamma radiation (as challenge dose).

Background/further details

Adaptive response: It is known that different cell types that were exposed to an extremely small adaptation dose of a genotoxic agent are less susceptible to the induction of a genetic damage when given a higher challenge dose of the same or similar genotoxic agent.
Mice were divided into 6 groups (n=10 per group): 1.) control group, 2.) gamma radiation alone (3 Gy, dose rate 0.5 Gy/min), 3.) radiofrequency exposure, 4.) radiofrequency exposure + gamma radiation, 5.) sham exposure and 6.) sham exposure + gamma radiation. Mice were sacrificed 72 hours after the last treatment to collect blood and bone marrow.

Endpoint

genotoxicity/mutation: DNA damage in erythrocytes and bone marrow cells

Exposure

- 900 MHz
- RF field
- co-exposure

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: CW Exposure duration: 4 h/day for 7 days	power density: 120 µW/cm² SAR: 548 mW/kg

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	4 h/day for 7 days

Modulation

Modulation type	CW

Exposure setup

Exposure source	GTEM cell
Chamber	each mouse was exposed individually in a small plastic box, placed on a non-conductive platform
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	120 µW/cm²	-	-	-	-
SAR	548 mW/kg	-	calculated	whole body	-

Reference articles

Cao Y et al. (2011): Induction of adaptive response: pre-exposure of mice to 900 MHz radiofrequency fields reduces hematopoietic damage caused by subsequent exposure to ionising radiation
Cao Y et al. (2010): Effects of 900-MHz Microwave Radiation on gamma-Ray-Induced Damage to Mouse Hematopoietic System

Exposed system:

animal
mouse/ICR
whole body

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: DNA damage in erythrocytes and bone marrow cells (micronuclei assay, acridine orange staining, fluorescence microscopy)

Investigated system:

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Combined exposures to radiofrequency and gamma radiation yielded in a significant decrease in the number of micronuclei in erythrocytes and bone marrow cells when compared to gamma radiated mice alone, whereas no such an effect was observed in sham exposed and gamma radiated mice.
The data indicate that there is a radiofrequency induced adaptive response in mice. Hence, pre-exposure to radiofrequency fields could be capable to protect the erythrocytes and bone marrow cells from genotoxic effects of a subsequent gamma radiation.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Ministry of Science and Technology (MOST), China
National Basic Research Program (Program 973), China
National Natural Science Foundation (NSFC), China
The Priority Academic Program Development of Jiangsu Higher Education Institutions, China

Zong C et al. (2015): Adaptive response in mice exposed to 900 MHz radiofrequency fields: Bleomycin-induced DNA and oxidative damage/repair
Mortazavi SM et al. (2014): Non-linear adaptive phenomena which decrease the risk of infection after pre-exposure to radiofrequency radiation
Sannino A et al. (2014): Adaptive response in human blood lymphocytes exposed to non-ionizing radiofrequency fields: resistance to ionizing radiation-induced damage
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