| With the development of mobile communication technology,the electromagnetic environment of human beings is more complex,and the safety of electromagnetic exposure is increasingly concerned by society.There are many reports on the effects of electromagnetic exposure on cognitive ability and reproductive function,most of which are based on short-term or acute exposure studies that limit animals.However,in the study of long-term non-restricted animals,the related research results are still controversial due to the complicated operation of the existing free animal exposure system,the unsuitable living environment of the exposed environment and the inaccurate characterization of the exposure dose of the free animal.The research work in this article investigated the effects of single and combined doses of radiation on the cognitive ability and reproductive function of rats in a free state under the conditions of ICNIRP occupational and public safety limits.This article first designed and developed an exposure system that allows rats to be in a free state for uninterrupted electromagnetic exposure,and can accurately control the dose of electromagnetic exposure to rats.The system uses video tracking recognition program to obtain the behavior of free animals.The electromagnetic exposure dose of free rats was calculated by weighted behavior time ratio.The results showed that the exposure dose was negatively correlated with body weight.In order to keep the constant dose of electromagnetic exposure,the system can adjust the exposure parameters according to the change of rat body weight by software installed on mobile phone and computer.At the same time,the uncertainty of numerical simulation and experimental measurement is analyzed in this paper.The deviation mainly comes from the inhomogeneity of model electrical parameters and electromagnetic field.The total uncertainty of the system is about 1.53 d B.During the exposure period,the temperature and humidity in the system remain constant(temperature 25±2°C,relative humidity 55±5%),noise is less than 10 dB,and animals can drink and eat freely.The uniformity of the electromagnetic field in the irradiated area is better,the maximum deviation of the electric field is less than 20%,and the maximum exposure efficiency is about 0.21(W/kg)/W,and the results of simulation and experimental measurement are more consistent.Based on this system,this article builds an all-day low-dose electromagnetic exposure environment to verify the reliability of the exposure system.At the same time,single(SAR=0.08 W/kg,24 h/d)and compound doses(Specific Absorption Ratio(SAR)=0.08 W/kg,16 h/d;SAR=0.4 W/kg,8 h/d;)The effect of electromagnetic exposure on the reproduction and learning and cognitive abilities of male rats during the developmental period.The exposure parameters refer to the occupational and public safety limits mentioned in the ICNIRP guidelines to assess their potential health risks.The experiment evaluated the learning and cognitive ability of rats through the water maze experiment,the detection of neurotransmitter and oxidative stress levels in the hippocampus,and the histopathological observation.The assessment of reproductive damage is based on the detection of sperm quality,serum testosterone levels,and oxidative stress levels in the testes.The results showed that there was no significant effect on the learning and cognitive ability of rats under single dose exposure,but the contents of dopamine(DA),serotonin(5-hydroxytryptamine)and brain-derived nutrition factor(BDNF)increased in hippocampus of rats after combined dose exposure,and the cholinergic related indexes changed significantly.However,the results of water maze showed that the change of neurotransmitter level was not reflected in learning and memory behavior,and the change returned to normal level within 14 d.After irradiation,the morphology of hippocampal tissue and the level of oxidative stress did not change,indicating that electromagnetic exposure can affect nervous system activity in a non-damaged way.Single and combined dose exposure can affect reproductive health,in which single exposure only reduces sperm quality and can recover quickly.the SOD activity in testicular tissue decreased and the MDA content increased after combined dose exposure(p<0.05).the sperm motility,survival rate and density in epididymis decreased,and the sperm malformation rate increased until 30 d after each index recovered.Although no effect of combined exposure on organ weight and serum testosterone level was found,tissue morphology observation showed that it had been damaged.The research results in this article show that although the electromagnetic exposure doses meet the ICNIRP guidelines for public and occupational safety limits,the combined dose of 8 h + 16 h can be used to treat rats in a free state after uninterrupted exposure throughout the day.The ability of learning and memory has an impact on the reproductive system. |
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