Reactive Oxygen Species Formation and Apoptosis in Human Peripheral Blood Mononuclear Cell Induced by 900 MHz Mobile Phone Radiation

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Research Article

Reactive Oxygen Species Formation and Apoptosis in Human Peripheral Blood

Mononuclear Cell Induced by 900 MHz Mobile Phone Radiation

http://www.hindawi.com/journals/oximed/2012/740280/

Yao-Sheng Lu,1,2 Bao-Tian Huang,1 and Yao-Xiong Huang1

1Department of Biomedical Engineering, Jinan University, Guangzhou 510632, 

China

2Department of Electronic Engineering, Jinan University, Guangzhou 510632, 

China

Received 12 February 2012; Accepted 10 April 2012

Academic Editor: Marcos Dias Pereira

Copyright © 2012 Yao-Sheng Lu et al. This is an open access article distributed

under the Creative Commons Attribution License, which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is

properly cited.

Abstract

We demonstrate that reactive oxygen species (ROS) plays an important role in the

process of apoptosis in human peripheral blood mononuclear cell (PBMC) which is

induced by the radiation of 900 MHz radiofrequency electromagnetic field (RFEMF)

at a specific absorption rate (SAR) of ~0.4 W/kg when the exposure lasts longer

than two hours.

The apoptosis is induced through the mitochondrial pathway and mediated by

activating ROS and caspase-3, and decreasing the mitochondrial potential. The

activation of ROS is triggered by the conformation disturbance of lipids,

protein, and DNA induced by the exposure of GSM RFEMF. Although human PBMC was

found to have a self-protection mechanism of releasing carotenoid in response to

oxidative stress to lessen the further increase of ROS, the imbalance between

the antioxidant defenses and ROS formation still results in an increase of cell

death with the exposure time and can cause about 37% human PBMC death in eight

hours.

1. Introduction

Mobile phones have been widely used in popular telecommunication and medical

telemetry systems. The tremendous use of mobile phone has drastically increased

the amount of radiofrequency electromagnetic field (GSM RFEMF) exposure in our

daily lives. To ensure telecommunication in anywhere, various kinds of mobile

phone relay stations or devices need to be placed inside or near living/working

and residential areas. It makes people have the possibility to be exposed to the

RFEMF radiation almost every moment. Thus there is a major concern about the

effects of RFEMF radiation exposure on human health. Despite previous studies,

our knowledge on these effects is still inadequate and strong debates continue

[1–5].Among the various health effects of GSM RFEMF exposure, the formation of

reactive oxygen species (ROS) and increased oxidative stress are those proposed

mechanisms that can explain the link between RFEMF radiation and possible

harmful effects on human health. It was found that RFEMF could induce ROS

formation in animal brain, cortical neurons, spleen, blood serum, and human

semen [6–10]. The purpose of this study was to investigate the extent of ROS

formation and oxidative DNA damage as well as cell apoptosis caused by RFEMF on

human peripheral blood mononuclear cell (PBMC). PBMC cells are a critical

component in the immune system to fight infection and adapt to intruders. They

also play significant roles in neurodegenerative diseases and aging [11–14].

Therefore, investigation of whether and how oxidative stress activates in PBMC

under the exposure of RFEMF radiation can help to further clarify its effects on

human health. In this study, isolated fresh human peripheral blood mononuclear

cells were exposed to the radiation of 900 MHz GSM RFEMF at a specific

absorption rate (SAR) of 0.4 W/kg for 1 h, 2 h, 4 h, 6 h, and 8 h. The specific

absorption rate was chosen to mimic the situation that people usually may absorb

in an environment within a distance of 20 meters from mobile phone relay

stations, or occupationally in an equipment room of microwave communication, or

around a surveillance radar [15–17]. It is also the occupational exposure

restriction suggested by the International Commission on Non-ionizing Radiation

Protection and some national radiological protection boards [18, 19].To detect

the intracellular ROS activation in the exposed cells, fluorescent dye DCFH was

used as the probe in flow cytometry. The caspase-3 activity of the cells was

assessed by colorimetric assay, while the cell apoptosis was analyzed by flow

cytometry with FITC-Annexin V/Propidium Iodide (PI) double staining. To assess

DNA damage of human PBMC and reveal the mechanism of the effect of RFEMF

radiation, confocal Raman microspectroscopy was also employed.

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