Effect of long-term 1.8 GHz combined electromagnetic radiation on the learning and cognitive ability of rats

Abstract

To provide experimental evidence that defines the safety limits of electromagnetic exposure, the effects of long-term and low-dose electromagnetic irradiation during the developmental stage of free-move behaving Sprague Dawley (SD) rats on their learning and cognitive abilities were investigated. A 1.8 GHz electromagnetic wave was used as the irradiation source, and the absorbed dose was set at 0.40 W/kg during the 8-hour working time and 0.08 W/kg during the rest time of the day, the whole irradiation was continuously administered for 4 weeks. The water maze experiment was performed to detect the learning and memory ability of the rats. The chemical colorimetric method was used to measure the level of cholinergic markers, the level of monoamine neurotransmitters, the activity of antioxidant enzymes, and the concentration of oxidative stress products in the hippocampus of the rats. In addition, the hippocampal tissue was sectioned, stained, and observed under an optical microscope. The results showed that the hippocampal tissue in the brain of the exposed group was not significantly different from that of the sham group, but the content of cholinesterase was reduced and the content of acetylcholine and the activity of acetylcholine transferase were increased in the exposed group. The contents of the neurotransmitter dopamine and serotonin (5-HT) were also significantly higher in the exposed group than those in the sham group. The water maze test results showed that there was no significant change in the behavior of rats in the exposed group. Although long-term and low-dose electromagnetic radiation can cause disorders of the cholinergic system and neurotransmitter levels in SD rats, the changes in these indicators did not cause a decline in the learning and memory ability of rats, and the levels of cholinergic system markers and neurotransmitters returned to normal after 14 days.

Keywords

• low-dose radiation
• morris water maze
• cholinergic system
• oxidative stress
• neurotransmitters