Authors

Bas O, Odaci E, Kaplan S, Acer N, Ucok K, Colakoglu S. 900 megahertz electromagnetic field exposure affects qualitative and quantitative features of hippocampal pyramidal cells in the adult female rat. Brain Res. Feb 18, 2009 Ahead of print.

Background
The use of mobile phones in modern culture is ubiquitous, and therefore, so is exposure to radiofrequency electromagnetic fields (RF-EMFs) emitted by these devices.  The potential side effects of RF-EMF exposure on brain tissues and the central nervous system (CNS) have received particular attention, owing to the fact that mobile phones are used in close proximity to the brain. Although many studies have been done in the field of toxicology, epidemiology, and cellular biology, the effects of EMF exposure on the CNS are still unclear.  In animal experiments, exposure to different forms of radiation have resulted in reversible or irreversible structural or functional changes to cells.  Some of these studies have focused on the hippocampus, the part of the brain that controls important behavioural and cognitive functions, including spatial learning and working memory. There is also evidence that females are more exposed to EMFs than males due to higher cell phone use.

Objective
To investigate the effects of postnatal exposure to EMF on the number of pyramidal cells in the hippocampus of 16-week-old female rats.

Methods
A total of 18 twelve-week old female rats were divided into 3 equal groups.  Rats in the exposure and sham group were placed in an exposure tube for 1 hour/day for 28 days.  Rats in the exposure group were exposed to 900MHz EMF while those in the sham group were not. Rats in the control group lived under normal laboratory conditions. At the end of the experiment, rats were euthanized and samples of their hippocampus were investigated under a microscope. Numbers of pyramidal cells were counted by analysts who were blind to the exposure status of rats.

Results
There was no significant difference in the weight of the rats between the 3 groups at the end of the experiment. The morphology of the pyramidal cells from rats in the sham exposure and control group was normal, while that of cells from rats in the exposure group was not. Furthermore, there was more evidence of neuron damage in brain samples of exposed rats. The total number of pyramidal cells was significantly lower among exposed rats than among sham exposed or control rats. There was no significant difference between control and sham exposed groups.

Interpretation and Limitations
Use of mobile phones among children and teenagers is especially a concern due to larger cumulative exposure to EMF than previous generations and due to the vulnerability of the brain’s development processes at the time of exposure. Use of 16-week old rates may be comparable with the age of human teenagers.  Results of this study suggest that exposure to EMF has effects on the brain at the cellular level.  This is similar to results of another study that used qualitative outcomes. Nonetheless, the current study was small and further research needs to be done.

Conclusion
Exposure to 900MHz EMF, a frequency similar to what is used by most mobile phones in Europe and other countries, resulted in neuronal damage and cell loss in the hippocampus of 16-week old female rats.


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