Medical/biological study (experimental study)

Induction of adaptive response in human blood lymphocytes exposed to radiofrequency radiation med./bio.

By: Sannino A, Sarti M, Reddy SB, Prihoda TJ, Vijayalaxmi, Scarfi MR

Published in: Radiat Res 2009; 171 (6): 735-742

Aim of study (acc. to author)

To study whether non-ionizing radiofrequency exposure, given as an adaptation dose for 20 h, renders the cells refractory to the genetic damage induced by a subsequent challenge dose with the genotoxic agent mitomycin C.

Background/further details

Adaptive response: Different cell types that were exposed to an extremely small adaptation dose of a genotoxic agent were found to be less susceptible to the induction of genetic damage when given a higher challenge dose of the same or similar genotoxic agent. The induction of an adaptive response was shown to be influenced by several factors (e.g. the dose used for adaptation, the dose rate, the time between the adaptation and challenge doses).
Lymphocytes of five different donors were investigated.

Endpoint

genotoxicity/mutation: DNA damage (micronucleus formation)

Exposure

- RF field
- mobile communications
- mobile phone

Exposure	Parameters
Exposure 1: 900 MHz Exposure duration: continuous for 20 h	SAR: 10 W/kg peak value SAR: 1.25 W/kg average over mass

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	continuous for 20 h

Exposure setup

Exposure source	wire patch cell
Setup	wire patch cell shielded by a metal grid box, placed inside an incubator
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	10 W/kg	peak value	measured and calculated	-	-
SAR	1.25 W/kg	average over mass	measured and calculated	-	-

Additional parameter details

The SAR value was chosen because it is the worst-case scenario for the exposure of the head region of a mobile phone user .

Reference articles

Palumbo R et al. (2008): Exposure to 900 MHz radiofrequency radiation induces caspase 3 activation in proliferating human lymphocytes
Scarfi MR et al. (2006): Exposure to radiofrequency radiation (900 MHz, GSM signal) does not affect micronucleus frequency and cell proliferation in human peripheral blood lymphocytes: an interlaboratory study

Exposed system:

intact cell/cell culture

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: micronucleus formation (cytokinesis block micronucleus assay; Giemsa stain; light microscopy)
cell viability/cell division/proliferation: cytotoxicity (proliferation index (M1+2M2+3(M3+M4)/total number of cells; M1 to M4: number of cells with 1 to 4 nuclei); binucleate cell index (percentage of binucleated cells))

Investigated system:

intact cell/cell culture
chromosomes

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Lymphocytes of four donors exhibited the induction of an adaptive response. Cells that were pre-exposed to 900 MHz radiofrequency irradiation had a significantly decreased incidence of micronuclei induced by the challenge dose of mitomycin C compared to those that were not pre-exposed to 900 MHz radiofrequency irradiation. However, induction of the adaptive response was not observed in the remaining fifth donor. The incidence of micronuclei induced by the challenge dose of mitomycin C was not significantly different between the pre-exposed and unexposed lymphocytes.
In conclusion, the data obtained in this preliminary investigation indicated that radiofrequency exposure at a frequency in use for wireless communications are capable of inducing an adaptive response in human blood lymphocytes. Further research is needed regarding whether an adaptive response can be elicited in other in vitro and in vivo experimental conditions (including various frequencies, different SAR values, timing of adaptation etc.).

Study character:

medical/biological study
experimental study
pilot/exploratory/preliminary study

Study funded by

not stated/no funding

Zong C et al. (2015): Adaptive response in mice exposed to 900 MHz radiofrequency fields: Bleomycin-induced DNA and oxidative damage/repair
Sannino A et al. (2014): Adaptive response in human blood lymphocytes exposed to non-ionizing radiofrequency fields: resistance to ionizing radiation-induced damage
Jiang B et al. (2013): Induction of adaptive response in mice exposed to 900MHz radiofrequency fields: application of micronucleus assay
Vijayalaxmi et al. (2013): Incidence of micronuclei in human peripheral blood lymphocytes exposed to modulated and unmodulated 2450 MHz radiofrequency fields
Jiang B et al. (2012): Adaptive Response in Mice Exposed to 900 MHz Radiofrequency Fields: Primary DNA Damage
Zeni O et al. (2012): Induction of an adaptive response in human blood lymphocytes exposed to radiofrequency fields: Influence of the universal mobile telecommunication system (UMTS) signal and the specific absorption rate
Sannino A et al. (2011): Induction of adaptive response in human blood lymphocytes exposed to 900 MHz radiofrequency fields: Influence of cell cycle
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Scarfi MR et al. (2006): Exposure to radiofrequency radiation (900 MHz, GSM signal) does not affect micronucleus frequency and cell proliferation in human peripheral blood lymphocytes: an interlaboratory study
Zeni O et al. (2005): Evaluation of genotoxic effects in human peripheral blood leukocytes following an acute in vitro exposure to 900 MHz radiofrequency fields
Baohong W et al. (2005): Studying the synergistic damage effects induced by 1.8 GHz radiofrequency field radiation (RFR) with four chemical mutagens on human lymphocyte DNA using comet assay in vitro
Gadhia PK et al. (2003): A Preliminary Study to Assess Possible Chromosomal Damage Among Users of Digital Mobile Phones