New rat study with implications for prolonged 900 MHz smart meter exposures
Effects of mobile phone radiation (900 MHz radiofrequency) on structure and functions of rat brain
Saikhedkar N, Bhatnagar M, Jain A, Sukhwal P, Sharma C, Jaiswal N. Effects of mobile phone radiation (900 MHz radiofrequency) on structure and functions of rat brain. Neurol Res. 2014 May 26:1743132814Y0000000392. [Epub ahead of print]
Objectives: The goals of this study were: (1) to obtain basic information about the effects of long-term use of mobile phone on cytological makeup of the hippocampus in rat brain (2) to evaluate the effects on antioxidant status, and (3) to evaluate the effects on cognitive behavior particularly on learning and memory.
Methods: Rats (age 30 days, 120 ± 5 g) were exposed to 900 MHz radio waves by means of a mobile hand set for 4 hours per day for 15 days. Effects on anxiety, spatial learning, and memory were studied using open field test, elevated plus maze, Morris water maze (MWM), and classic maze test. Effects on brain antioxidant status were also studied. Cresyl violet staining was done to access the neuronal damage.
Result: A significant change in behavior, i.e., more anxiety and poor learning was shown by test animals as compared to controls and sham group. A significant change in level of antioxidant enzymes and non-enzymatic antioxidants, and increase in lipid peroxidation were observed in test rats. Histological examination showed neurodegenerative cells in hippocampal sub regions and cerebral cortex.
Discussion: Thus our findings indicate extensive neurodegeneration on exposure to radio waves. Increased production of reactive oxygen species due to exhaustion of enzymatic and non-enzymatic antioxidants and increased lipid peroxidation are indicating extensive neurodegeneration in selective areas of CA1, CA3, DG, and cerebral cortex. This extensive neuronal damage results in alterations in behavior related to memory and learning.
Rats were exposed continuously to 900 MHz frequency emitted from the handset at a SAR of approximately 0·9 W/kg. Rats were exposed for 15 days daily at a rate of 4 hours per day (9·00 AM to 13·00 PM). Control rats were not given any exposure. Sham group rats underwent exposure in the same way as experimental rats but mobile phone fitted in the cage was switched off. Rats were exposed to mobile phone EMR at a frequency of 900 MHz and an average SAR of 0·99 W/kg
The results demonstrated marked effects on behavior, which could be correlated to physiological as well cellular changes. For behavioral study, open field test, water maze, elevated plus maze were carried out. In open field test, time spent in the center of the open field (center-stay time) indicated general anxiety. The number of entries made in different zones of the open field is also taken as parameter of anxious locomotor behavior. Also, the number of defecations and urinations is connected to anxiety. The number of crossed squares in the test field, shows the locomotor activity and the number of times the rat lifts its fore paws, is regarded as a general exploratory behavior.11,13,27 In our study, test rats showed an increase in locomotion, and spent more time in center as compared to controls, which preferred to stay in one corner of the open field. Test animals also showed increased rearing and grooming, which explains increase in exploratory behavior. Moreover, test rats defecated in a larger quantity and at abnormal time as compared to controls, which defecated only at the time of entry. These changes indicate disturbed or ‘non emotional’ state of the test rats.17,28 The non emotionality of rats was also visible by the stretch-attend postures and freezing behavior shown by test animals.
The neurotoxic and behavioral effects of mobile radiations are well explained by the results of histological study. The brain of exposed animals exhibited intense neurodegeneration in the hippocampal region, especially in DG, CA1, and CA3. Cerebral cortex also showed a significant neuronal damage … Cell damage in hippocampus provides a clue for understanding the behavioral changes in test rats. Similarly, cortex is also responsible for memory, attention, perceptual awareness, thought, language, and consciousness. Neurodegeneration in this region will lead to disturbance of mental state as observed in open field tests and changes in sleep pattern of exposed animals. Presence of oxidative stress is responsible for neurodegeneration, owing to increased production of reactive oxygen species in the cell and exhaustion of enzymes SOD and CAT. The possibility of oxidative damage is higher especially since MDA levels are increasing, could be because of increased lipid peroxidation.
Although, our study comprises of few animals, results are significant. We have also preferred young rats as these could simulate current teenagers and physiological functioning of their brain. The adverse effects on the growing brain should deserve special concern from society because biological processes are particularly vulnerable during the growth process. The intense use of mobile phones by youngsters is thus a serious consideration. A neuronal damage of the kind described here may not have immediate demonstrable consequences, but in the long run it may result in reduced brain reserve capacity that might be unveiled by other late neuronal diseases. We cannot exclude the possibility that after some decades of daily (often) use, a whole generation of users may suffer from the negative effects, perhaps as early as in middle age.