Wetenschappelijk nieuws
Cell phone radiation (900 MHz GSM) causes oxidative stress in discrete brain regions of rats
- Gegevens
- Gepubliceerd: dinsdag 30 september 2014 07:53
Bratislava Medical Journal. 2014;115(5):260-6.
RESULTS: Altered behavioral performances were found in RF-EMR-exposed rats. Additionally, elevated TBARS level was found with all brain regions studied. RF-EMR exposure significantly decreased TA in the amygdala and cerebellum but its level was not significantly changed in other brain regions. GST activity was significantly decreased in the hippocampus but, its activity was unaltered in other brain regions studied.
CONCLUSION: RF-EMR exposure for a month induced oxidative stress in rat brain, but its magnitude was different in different regions studied. RF-EMR-induced oxidative stress could be one of the underlying causes for the behavioral deficits seen in rats after RF-EMR exposure (Fig. 5, Ref. 37).
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S. N. Narayanan, R. S. Kumar, V. Kedage, K. Nalini, S. Nayak, P. G. Bhat. Evaluation of oxidant stress and antioxidant defense in discrete brain regions of rats exposed to 900 MHz radiation. Bratislava Medical Journal. 2014;115(5):260-6.
Abstract
AIM: In the current study, the effects of 900 MHz radio-frequency electromagnetic radiation (RF-EMR) on levels of thiobarbituric acid-reactive substances (TBARS), total antioxidants (TA), and glutathione S-transferase (GST) activity in discrete brain regions were studied in adolescent rats.
MATERIALS AND METHODS: Thirty-six male Wistar rats (6-8 weeks old) were allotted into three groups (n = 12 in each group). Control group (1) remained undisturbed in their home cage; sham group (2) was exposed to mobile phone in switch off mode for four weeks; RF-EMR-exposed group (3) was exposed to 900 MHz of RF-EMR (1 hr/day with peak power density of 146.60 µW/cm2) from an activated Global System for Mobile communication (GSM) mobile phone (kept in silent mode; no ring tone and no vibration) for four weeks. On 29th day, behavioral analysis was done. Followed by this, six animals from each group were sacrificed and biochemical parameters were studied in amygdala, hippocampus, frontal cortex, and cerebellum.
RESULTS: Altered behavioral performances were found in RF-EMR-exposed rats. Additionally, elevated TBARS level was found with all brain regions studied. RF-EMR exposure significantly decreased TA in the amygdala and cerebellum but its level was not significantly changed in other brain regions. GST activity was significantly decreased in the hippocampus but, its activity was unaltered in other brain regions studied.
CONCLUSION: RF-EMR exposure for a month induced oxidative stress in rat brain, but its magnitude was different in different regions studied. RF-EMR-induced oxidative stress could be one of the underlying causes for the behavioral deficits seen in rats after RF-EMR exposure (Fig. 5, Ref. 37).
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Excerpts
RF-EMR exposed group was exposed to 900 MHz radiation from an active mobile phone. RF-EMR exposure by the downlink frequency band (890 to 915 MHz with basic band of 900 MHz) of GSM was studied. The exposure of rats was achieved by placing the phone in a wood bottom bamboo wire mesh cage (12 cm × 7 cm × 7 cm) in the center of the home cage (which has 3 ratsin it). This was done carefully to prevent the rats from getting in direct contact with the device. A level 4 GSM mobile phone witha permitted power level of 2 W (with SAR specification 1.58 W/kg) was used for this purpose. Animals were exposed to 900 MHz RF-EMR by giving 50 missed calls or unattended calls (within one hour) per day for 28 days. The phone was kept in silent mode (no ring tone and no vibration) and was allowed to ring ~45 secondsduring each call, followed by a 15-second interval before next call. This process was repeated 50 times ... The peak power densityrecorded from the vicinity of the mobile phone (3 cm away from the phone) was found to be 146.60 μW/cm2. When the cell phone was not activated but in ‘ON’ mode, the peak power density was found to be 2.109 nW/cm2 (18).
Upon critically evaluating the results obtained in the current study, it is evident that all brain regions studied had an elevated TBARS concentration in RF-EMR exposed rats compared to control and sham rats. An elevated level of TBARS is an index of lipid peroxidation in these regions. It was maximally elevated in the frontal cortex (Fig. 5A) and in amygdala when compared to other brain regions of RF-EMR exposed rats. This indirectly points to the fact that 900 MHz RF-EMR exposure induced either generation of excess ROS or decreased removal of ROS in different brain regions.
... it was evident from the current results that oxidant-antioxidant balance was altered significantly in prefrontal cortex and amygdala, while these brain regions regulate the emotionality (28) of organism ... we believe that one of the reasons for behavioral alteration seen in rats after RF-EMR exposure is due to oxidative stress induced by RF-EMR in these brain regions.
The effect of RF-EMR–induced oxidative stress is a concern due to reasons as follows: 1) It could interfere with the learning and memory processes (32); 2) It may also accelerate various neurodegenerative diseases (33); 3) It might impair and oxidize DNA, lipids, sugars and proteins and consequently result in dysfunction ofthese molecules within cells and finally bring on cell death in various organs (34); 4) It could be a probable tumor promoter (35, 36).
Conclusion
Results of the current study clearly demonstrate that, RF-EMR exposure for a period of one month induced excessive lipid peoxidation and decreased antioxidants defense status in different brain regions of rats. We also conclude that oxidative stress could be one of the underlying mechanisms for behavioral alterationsseen in rats after RF-EMR exposure. It is advisable to have a precautionary measure to reduce continuous and chronic exposure to RF-EMR from mobile phone and other RF-EMR emitting devices.