Watilliaux A, Edeline JM, Leveque P, Jay TM, Mallat M. Effect of exposure to 1,800 MHz electromagnetic fields on heat shock proteins and glial cells in the brain of developing rats. Neurotox Res. Ahead of print. Nov 2, 2010.
Increases in mobile phone ownership among adolescents have raised concerns about the potential vulnerability of young people to radiofrequency (RF) fields associated with their use. Most studies aiming to evaluate children’s sensitivity to RF have focussed on cancer.
The objective of this study was to determine whether a Global System for Mobile Communications (GSM) 1,800 MHz electromagnetic field (EMF) affects immature rodent brains when applied at various stages of postnatal development.
Young rats were exposed to EMF on postnatal days (P) 5 (n = 6), 15 (n = 5) or 35 (n = 6) and were compared to pseudo-exposed littermate rats (n = 6 at all ages). A single exposure to the head was conducted for 2 h using a GSM 1,800 MHz signal at a brain average specific absorption rate (SAR) in the range of 1.7 to 2.5 W/kg. Animals were anaesthetised during the exposure to prevent movement. Rats were sacrificed 24 hours after exposure, brains were dissected, and protein was extracted. Western blotting was performed to detect heat shock proteins (HSPs) and cytoskeleton- or neurotransmission-related proteins in the developing astroglia, and imunohistochemical methods were used to determine glial cell responses.
The GSM signal had no significant effect on the abundance of HSPs 60, 90, or 70. It also had no significant effect on serine racemase or glutamate transporters, astrocyte functions related to excitatory neurotransmission. Glial fibrillary acid protein, a cell marker of astrocyte differentiation, also showed no effect due to treatment in either total or soluble tissue extracts. Imunohistochemical detection of CD68 antigen in brain sections from pseudo-exposed and exposed animals did not reveal any differences in the morphology or distribution of microglial cells.
Interpretation and Limitations
The results of this study provide no evidence for acute cell stress or glial reactions indicative of early neural cell damage in developing rat brains. This study is the first assessment of acute CNS tissue reactions in immature brain to a GSM 1,800 MHz signal. Previous studies have indicated that astroglial cells are directly or indirectly responsive to EMF however, these studies have been conducted using a GSM of 900 MHz for longer durations of time in adult animals with higher SARs. One limitation of this study is that the study was performed with anaesthetised animals and the anaesthesia may have interfered with the neural cell responses to EMF. Other limitations are that the duration of exposure was short and that it is difficult to extrapolate these results to humans.
This study suggests that short term exposure to a GSM 1,800 MHz signal does not cause neurotoxic effects in developing rat brains.