Medical/biological Study (experimental study)

Induction of adaptive response: pre-exposure of mice to 900 MHz radiofrequency fields reduces hematopoietic damage caused by subsequent exposure to ionising radiation. med./biol.

PubMed Entry

Journal web site

Aim of study (according to author)
To study whether an adaptive response can be induced in mice which were pre-exposed to 900 MHz radiofrequency fields and to determine the optimal power intensity needed for radiofrequency pre-exposure in order to achieve considerable "protection" from subsequent ionizing radiation-induced damage.
Background/further details:
For the survival experiment, a total of 140 mice were divided into the following five groups (each group n=28): 1) 8 Gy gamma radiation alone (lethal dose), 2) radiofrequency exposure at 12 µW/cm² + gamma radiation on day 15 after the last day of exposure, 3) radiofrequency exposure at 120 µW/cm² + gamma radiation on day 15, 4) radiofrequency exposure at 1200 µW/cm² + gamma radiation on day 15, 5) positive control (free radical scavenger treatment (amifostine) + gamma radiation.
For all other experiments 144 animals were divided into the following groups (each group n=12): 1) three groups of unexposed controls, 2) 8 Gy gamma radiation (lethal dose; for organ weight evaluation) or 5 Gy gamma radiation (for all other experiments) on day 15, 3) three groups of 120 µW/cm² radiofrequency exposure (for all experiments), 4) one group at 120 µW/cm² radiofrequency exposure + 8 Gy gamma radiation (lethal dose; for organ weight evaluation) or two groups at at 120 µW/cm² radiofrequency exposure + 5 Gy gamma radiation (for colony forming units in bone marrow cells and gene expression) on day 15.
Additionally, for evaluation of colony forming units in the spleen of lethally irradiated "recipient" mice, 12 donor mice (each group n=3) were divided into 1) an unexposed control group, 2) 5 Gy gamma radiation only group, 3) group of 120 µW/cm² radiofrequency exposure and 4) group of 120 µW/cm² radiofrequency exposure + 5 Gy gamma radiation. Following gamma radiation, the mice were sacrificed, the nucletaed cells of the bone marrow were collected, pooled for each group and injected in the tail vein of recipient mice (each group n=10). Recipient mice were exposed to a lethal dose of 8.5 Gy gamma radiation 4-6 h before injection of bone marrow cells.

Endpoints

• effects on immunological system: effects on hematopoietic system
• others: survival

Exposure
General category: radio frequency field, microwaves, CW (continuous wave), co-exposure

Field characteristics	Parameters
field 1: 900 MHz continuous wave (CW) exposure duration: continuous for 1 h/day for 14 days survival experiment	power flux density: 12 µW/cm² power flux density: 120 µW/cm² power flux density: 1200 µW/cm² SAR: 5.48 mW/kg (whole body) (for 12 µW/cm²) SAR: 54.8 mW/kg (whole body) (for 120 µW/cm²) SAR: 548 mW/kg (whole body) (for 1200 µW/cm²)
field 2: 900 MHz continuous wave (CW) exposure duration: continuous for 1 h/day for 14 days all other experiments	power flux density: 120 µW/cm² SAR: 54.8 mW/kg (whole body)

Exposed system:
animal (species/strain): mouse/Kunming
whole body exposure

Methods
Endpoint/Measurement parameters/Methodology

• molecular biosynthesis: cell cycle related gene expression (different cyclins; on day 3, 6, 9 and 12 after exposure (each day three mice); RT-PCR)
• effects on immunological system: effects on hematopoietic system (colony forming units (of hematopoietic progenitor cells) in nucletaed cells in bone marrow on day 3, 6, 9 and 12 after exposure (each day three mice) and colony forming units in the spleen of lethally irradiated recipient mice (as index of viable pluripotent hemopoietic stem cells or progenitor cells)), organ weights of thymus and spleen
• others: survival

Main outcome of study (according to author)
The data indicated significant increases in survival time, in the weights of spleen and thymus, number of colony forming units in the bone marrow and spleen of lethally irradiated recipient mice, and a reduction in the hematopoietic tissue damage in radiofrequency pre-exposed mice (120 µW/cm²) which were gamma radiated (as compared with those exposed to gamma radiation alone). This was accompanied by significantly increased expression of cell cycle-related genes (different cyclins) in hematopoietic cells. The findings suggested that the 120 µW/cm² power intensity for 900 MHz radiofrequency pre-exposure was adequate and optimum to lead to the maximum protection of hematopoietic tissue damage induced by subsequent exposure to gamma radiation.
The authors conclude, that pre-exposure of mice to 900 MHz radiofrequency fields has resulted in a significant reduction in hematopoietic damage caused by subsequent exposure to ionizing radiation. This phenomenon appears to be similar to that of the "adaptive response" which is well documented in scientific literature.

(Study character: medical/biological study, experimental study, full/main study, blind study)

Study funded by

• Ministry of Science and Technology (MOST), China
• National Natural Science Foundation (NSFC), China
• Soochow University, China

• Jiang B et al. (2012): Adaptive Response in Mice Exposed to 900 MHz Radiofrequency Fields: Primary DNA...
• Zeni O et al. (2012): Induction of an adaptive response in human blood lymphocytes exposed to...
• Sannino A et al. (2011): Induction of adaptive response in human blood lymphocytes exposed to 900 MHz...
• Kumar G et al. (2011): Evaluation of hematopoietic system effects after in vitro radiofrequency...
• Cao Y et al. (2010): Effects of 900-MHz Microwave Radiation on gamma-Ray-Induced Damage to Mouse...
• Cao Y et al. (2009): 900-MHz microwave radiation enhances gamma-ray adverse effects on SHG44 cells.
• Kouzmanova M et al. (2007): Effects of in vitro exposure to GSM900 electromagnetic field on human...
• Meng QQ et al. (2007): Combined Effects of Microwave and Ionizing Radiation on Mouse.
• Maes A et al. (2001): Cytogenetic effects of 900 MHz (GSM) microwaves on human lymphocytes.
• Fucic A et al. (1992): X-rays, microwaves and vinyl chloride monomer: their clastogenic and aneugenic...
• Rotkovska D et al. (1977): Modification of repair of X-irradiation damage of hemopoietic system of mice by...
• Rotkovska D et al. (1975): The effect of electromagnetic radiation on the hematopoietic stem cells of...
• Thomson RA et al. (1966): Leukocyte response following simultaneous ionizing and microwave (radar)...
• Thomson RA et al. (1965): Modification of X-Irradiation Lethality in Mice by Microwaves (Radar)
• Michaelson SM et al. (1963): The influence of microwaves on ionizing radiation exposure.