纳米硒和纳米铈联合应用对射频场暴露小鼠学习记忆的防护作用研究

PROTECTIVE EFFECTS OF NANO-SELENIUM COMBINED WITH NANO-CERIUM ON LEARNING AND MEMORY IN MICE EXPOSED TO RADIOFREQUENCY FIELD

目的研究纳米硒和纳米铈(纳米氧化铈)联合作用对1.8GHz射频场(radiofrequency field,RF)辐射小鼠学习记忆功能的影响,并探讨其防护作用机制。方法将63只6 w龄雄性健康清洁级ICR小鼠分为9组:空白对照组、溶剂对照组、RF辐射模型组、纳米铈单独作用和纳米硒铈联合作用各自的低、中、高三个剂量组。纳米硒铈联合作用低、中、高剂量组分别每天分别在7:30和18:30灌胃0.5 ml的纳米硒溶液(60、120和240μg/kg)和0.5 ml纳米氧化铈溶液(15、30、60μg/kg),连续14d,纳米铈单独作用相同时间点灌胃等量溶剂和纳米氧化铈溶液,空白对照组灌胃等体积蒸馏水,溶剂对照组和RF辐射组灌胃等体积溶剂。第8d,将RF组、纳米铈单独作用组、纳米硒铈联合作用组小鼠暴露于1.8GHz射频场(240μw/cm2,SAR:0.2999W/kg),每天2h,连续7d。辐射结束后利用Y型迷宫实验测定各组小鼠的学习记忆能力,同时测定小鼠大脑组织抗氧化指标(CAT,MDA和T-AOC)和神经递质(NO和GLU)。结果与溶剂对照组相比,RF辐射组小鼠学习次数增加,记忆率下降,大脑CAT活性和T-AOC水平下降,MDA含量增加,NO含量上升。与RF辐射模型组相比,纳米铈单独作用和纳米硒铈联合作用均使小鼠的学习次数减少,记忆率增加,大脑CAT活性和T-AOC水平上升,MDA和NO含量下降,GLU含量显著下降,且纳米硒和纳米铈联合作用效果优于纳米铈单独作用,其中中剂量组的改善幅度最大。结论纳米硒和纳米铈联合作用可改善由RF辐射所造成的学习记忆能力损伤,其中中剂量组(120μg/kg纳米硒和30μg/kg纳米氧化铈)效果最佳,其作用机制可能与增加大脑抗氧化水平,减少超氧自由基氧化损伤,并改善神经递质分泌有关,且其效果优于单独纳米铈作用.

Objective To study the combined effects of nanoselenium and nanocerium(nano cerium oxide)on learning and memory ability of mice exposed to 1.8 GHz radiofrequency fields(RFs),and explore its mechanism of protection.Methods Sixty-three 6-week-old male healthy ICR mice were divided into nine groups:blank control group,solvent control group,RF radiation group,low,medium and high dose groups of nanocerium,low,medium and high dose groups of nanoselenium and nanocerium.The low,medium and high doses of nanoselenium and nanocerium groups were administrated orally at 7:30 and 18:30 every day,with 0.5 ml of 60,120 and 240μg/kg nano selenium and 0.5 ml of 15,30,60μg/kg nanocerium for 14 days.The nanocerium groups were given the same amount of solvent and nanocerium solution at the same time.The blank control group was administrated orally with a same volume of distilled water,while the solvent control group and the RF radiation group were administered orally with a same volume of solvent solution.On the 8 th day,the mice in the RF radiation group,three nanocerium groups and three nanoselenium and nanocerium groups were exposed to 1.8 GHz RF(SAR:0.2999 W/kg)for 2 hours every day for 7 days.After treatment,the cognitive ability of the mice was tested by Y-maze test.Moreover,the antioxidant parameters(CAT,MDA,T-AOC)and neurotransmitters(NO,GLU)in the brain tissues of these mice were measured.Results Compared with the solvent control group,the mice in the RF radiation group had a poor learning ability,and a lower memory rate,decreased CAT activity and T-AOC level,but increased MDA and NO content in the brain tissue.Compared with the RF radiation model group,the single action of nanocerium and the combined action of nanoselenium and nanocerium led to increased learning,and memory rate,as well as improved CAT activities and T-AOC level,reduced MDA and NO content and decreased GLU content significantly in the brain tissue.The combined effect of nano-selenium and cerium was better than that of nanocerium alone.The medium dose group showed the greatest improvement.Conclusion The combined action of nanoselenium and nanocerium is effective in improving the learning and memory ability of mice exposed to RF,and the middle-dose group(120μg/kg nano-selenium and 30μg/kg nano-cerium oxide)has the best effect.The mechanism is related to increased brain antioxidant levels,reduction of superoxide radical oxidative damage,and regulation of neurotransmitter secretion.[ACTA NUTRIMENTA SINICA,2020,42(4):356-362]