The effects of electromagnetic radiations emitted from 3G mobile phones on visual evoked potentials

Over the past decade, the increase of mobile phone use due to the developing technology and requirement of communication has raised concern about the biological and healh-related effects of electromagnetic fields (EMF) emmitted by mobile phones, particularly on the brain tissue. Depending on the exposure duration and strength of EMF, contradictory results such as increased, decreased and unchanged lipid peroxidation and antioxidant enzyme activities in various tissue types have been reported in the literature. In addition, there are a limited number of studies about the effects of EMFs on the brain. Furthermore, no such study regarding the effects of 2100MHz EMF on the rat visual evoked potentials (VEP) has been encountered. Therefore, the purpose of our study was to investigate the effect of 2100-MHz EMFs on VEPs and to examine the relationship between lipid peroxidation and changes of these potentials as well as to elucidate the role of nitric oxide (NO) on oxidative stress. In our study, 80 male Wistar albino rats, 2 moths old, were randomly divided into four groups as 1 week of Sham exposure (S1), 1 week of EMF exposure (E1), 10 weeks of Sham exposure(S10) and 10 weeks of EMF exposure. E1 and E10 groups were exposed to 2100-MHz EMFs (2 h/day x 7 days/ week) while S1 and S10 were kept under the same experimental conditions without being exposed to EMF for 1 and 10 weeks, respectively. At the end of experimental period, rats were anesthetized with ketamine/xylazine (50 mg/kg: 10 mg/kg) and VEPs were recorded with stainless steel subdermal electrodes. Afterwards, brain tissues were collected for further biochemical and histological analysis. Compared to S1 group, brain TBARS and 4-HNE levels were significantly decreased and, protein carbonyl (PC) levels were increased in E1 group. On the other hand, TBARS, 4-HNE and PC levels in E10 group were increased when compared with S10 group, however, only the increase of TBARS and 4-HNE levels were found to be statistically significant. Brain CAT, GSH-Px, NO and GSH levels were significantly higher whereas SOD activity was significantly lower in the E1 group compared with S1 group. Nevertheless, higher SOD enzyme activity and lower CAT, GSH-Px, NO and GSH levels were observed in the E10 group compared with S10 group. Latencies of all VEP components were shortened in the E1 group compared with the S1 group, whereas latencies of all VEP components, except P1 component, were prolonged in the E10 group compared with the S10 group. As a result of the statistical analysis there was a positive correlation between all VEP latencies and brain TBARS and 4-HNE values. Therefore, from our study, it could be concluded that effects of EMFs on VEPs are exposure duration dependent. Additionally, our results indicated that while short-term EMFs exposure could provide beneficial effects, long-term EMFs exposure had an adverse effects on VEPs.