Research On The Effects And Mechanism Of Long-term Low Power Microwave Radiation On Learning And Memory In Rats

Objective:To investigate the effects of long-term low power microwave radiation on learning and memory in rats,and to explore its mechanism.Methods:60 SPF male Wistar rats were divided into four groups:sham radiation group,2.5 mW/cm2 microwave radiation group,5 mW/cm2 microwave radiation group and 10 mW/cm2 microwave radiation group.Each group was irradiated for 2 h/d and continuously for 1 m.An animal model of learning and memory disorders was constructed.On the 1 day,10 day and 20 day after irradiation,the eight-arm maze was used to test the learning and memory ability of rats.Changes of Asp,Glu,GABA and Gly neurotransmitters in the hippocampal DG region of rats were detected by microdialysis and high performance liquid chromatography.The tissue structure of hippocampus was observed by HE staining.The expression of Ras/ERK pathway protein in hippocampus was detected by Western blot.Result:The results of eight-arm maze showed that compared with the sham-irradiated rats,the number of working memory errors,reference memory errors and total number of progressive arms of rats in 2.5,5 and 10 mW/cm2 groups increased significantly on the 1 day,10 day and 20 day after microwave irradiation,especially in 5 and 10 mW/cm2 groups(P<0.05 or P<0.01).Working memory and reference memory did not recover within 20 days after irradiation.Microdialysis showed that the levels of Glu,Gly and GABA in rats exposed to 2.5,5 and 10 mW/cm2 on the 1 day,10 day and 20 day were higher than those in rats exposed to sham radiation(P<0.05 or P<0.01).The content of Asp on 1 day after irradiation was higher than that in the sham group(P<0.05 or P<0.01),but on the 10 day and 20 day,the content of Asp was lower than that in the sham group(P<0.01).After HE staining,the neurons in the hippocampus DG region of the 2.5,5 and 10 mW/cm2 groups were observed to have condensed and deep-stained neurons.The radiation intensity increased with the increase of radiation power.No recovery trend was observed within 20 days after radiation.Western Blot showed that the expressions of Ras,Raf-1,MEK and ERX1/2 in 2.5,5 and 10 mW/cm2 groups were higher than those in sham radiation group(P<0.05 or P<0.01),and the expressions of Ras,Raf-1,MEK and ERK1/2 increased with the increase of radiation dose.Within 20 days after irradiation,Ras,Raf-1,MEK and ERK1/2 proteins did not recover.Conclusion:Long-term low power microwave irradiation can reduce the learning and memory ability of rats,damage hippocampal tissue structure,and change the content of amino acid neurotransmitters in DG region of hippocampus.The mechanism may be related to the increased expression of Ras,Raf-1,MEK and ERK1/2 proteins in Ras/ERK signaling pathway induced by microwave radiation.It provides new goals and ideas for further research on damage mechanism and prevention measures of long-tero low power microwave radiation.