Cognitive impairment in rats after long‐term exposure to GSM‐900 mobile phone radiation

Abstract

Considering the frequent use of mobile phones, we have directed attention to possible implications on cognitive functions. In this study we investigated in a rat model the long-term effects of protracted exposure to Global System for Mobile Communication-900 MHz (GSM-900) radiation. Out of a total of 56 rats, 32 were exposed for 2 h each week for 55 weeks to radio-frequency electromagnetic radiation at different SAR levels (0.6 and 60 mW/kg at the initiation of the experimental period) emitted by a (GSM-900) test phone. Sixteen animals were sham exposed and eight animals were cage controls, which never left the animal house. After this protracted exposure, GSM-900 exposed rats were compared to sham exposed controls. Effects on exploratory behaviour were evaluated in the open-field test, in which no difference was seen. Effects on cognitive functions were evaluated in the episodic-like memory test. In our study, GSM exposed rats had impaired memory for objects and their temporal order of presentation, compared to sham exposed controls (P = 0.02). Detecting the place in which an object was presented was not affected by GSM exposure. Our results suggest significantly reduced memory functions in rats after GSM microwave exposure (P = 0.02).

Histopathological examinations of rat brains after long-term exposure to GSM-900 mobile phone radiation

“…We have previously seen in the same animals that the performance in the test trial of the episodic-like memory test (as seen by the standardised difference between old familiar object exploration time and recent familiar object exploration time) is significantly impaired in the GSM exposed animals as compared to the sham exposed animals [17]. There was no statistically significant difference in the exploration time between the higher and lower GSM exposed animals.…”

“…These TEM-cells have been designed by dimensional scaling from previously constructed cells at the National Bureau of Standards [6], which are known to generate uniform TEM-fields for standard measurements. The experimental setup has been described in detail in the first part of the present long term study that reported on cognitive effect after repeated exposure [17]. In short, a GSM mobile test phone with a programmable power output, at the frequency of 900 MHz, was connected to a power splitter, which divides the power into equal parts fed into the four TEM-cells used.…”

“…The performance in the third test trial of the episodic-like memory teat is compared by using the standardised difference between old familiar object exploration time and recent familiar object exploration time and between displaced and nondisplaced objects [17].…”

“…iii. Thirdly, in this study we also investigate to what extent histopathological findings might explain the reduced cognitive capacities observed in the episodic-like memory test [17]. Therefore, correlation analyses between each of the histopathological parameters mentioned above and the performance in the episodic-like memory test have been undertaken.…”

“…We have used the same exposure system as in the majority of our previous studies, with the awake, non-anaesthetised animals placed in transverse electromagnetic transmission line chambers (TEM-cells). After this protracted period, all animals were studied for behavioural and cognitive functions [17]. In summary, effects upon behaviour such as anxiety, locomotor activity and general exploratory behaviour, were evaluated in an open-field test, in which no difference was seen between the GSM exposed animals as compared to the sham group.…”