L和C波段微波复合暴露对大鼠认知功能和海马树突棘结构的影响

Effects of L and C-band microwave exposure on the cognitive function and hippocampal dendritic spine structure in rats

目的 探讨L和C波段微波复合暴露对大鼠认知功能和海马树突棘结构的影响。方法 采用平均功率密度为30 mW/cm^(2)的L和C波段微波单独/复合暴露二级雄性Wistar大鼠128只,照射时间为6 min。采用Morris水迷宫检测空间学习记忆功能,旷场和高架十字迷宫评价情绪;于照后6 h、7 d、14 d和1个月采用Golgi染色观察海马树突棘结构。结果 30 mW/cm^(2)的L波段微波照射6 min后2 d, Morris水迷宫大鼠平均逃避潜伏期缩短(P<0.05);L波段与C+L波段复合暴露后6 h,大鼠在旷场中央区探索时间和路程延长(P<0.05);C波段照射后3 d,大鼠在高架十字迷宫开放臂停留时间延长(P<0.05)。C波段单独照射后6 h,海马颗粒细胞树突棘密度增加,锥体细胞蘑菇状树突棘比例增加,14 d时颗粒细胞和锥体细胞蘑菇状树突棘比例均增加(P<0.05或P<0.01),1个月时颗粒细胞树突棘密度增加(P<0.05);L波段照射后7 d,颗粒细胞树突棘密度减低,14 d时锥体细胞树突棘密度降低,颗粒细胞蘑菇状树突棘比例增加(P<0.05或P<0.01);C+L波段复合暴露后14 d,锥体细胞和颗粒细胞蘑菇状树突棘比例增加(P<0.05)。结论 30 mW/cm^(2)的L和C波段微波单独或复合暴露对大鼠空间学习记忆能力无明显影响;L波段单独与L和C波段复合暴露可缓解大鼠焦虑情绪;L和C波段微波单独或复合暴露对大鼠海马树突棘结构的影响存在频率差异性。

Objectivee To investigate the effects of C and/or L-band microwave exposure on the cognitive function and hippocampal dendritic spine structure in rats.Methods 128 male Wistar rats were exposed to L and/or C band microwave with an average power density of 30 mW/cm^(2)for 6 minutes.Morris water maze was used to inspect spatial learning and memory functions.Emotion was examined by an open field and elevated cross maze.Golgi staining was used to observe the structure of hippocampal dendritic spine 6 hours,7 days,14 days,and 1 month after exposure.Results After L-band,C-band and C+L-band exposure for 6 min at 30 mW/cm^(2),the mean escape latency was significantly shorter in the L group 2 d after microwave exposure(P<0.05).The exploration time and distance in the central area of the open field was significantly longer in the L and C+L groups(P<0.05).Staying time in the elevated cruciform maze was significantly prolonged in the C group(P<0.05).Six hours after C-band exposure,the density of dendritic spine of hippocampal granule cells and the proportion of mushroom-like dendritic spine of pyramidal cells increased.On the 14th day,the proportion of mushroom-like dendritic spine of granule cells and pyramidal cells increased(P<0.05 or P<0.01),and the density of dendritic spine of granule cells increased after one month(P<0.05).On the 7th day after L band irradiation,the density of dendritic spine in granule cells decreased.On the 14th day,the density of dendritic spine in pyramidal cells decreased,and the proportion of mushroom like dendritic spine in granule cells increased(P<0.05 or P<0.01).14 days after C+L band combined exposure,the proportion of mushroom-like dendritic spine in pyramidal cells and granule cells increased(P<0.05).Conclusionss Exposure to30mW/cm^(2)of Land C-band microwaves alone or in combination for 6 min had no effect on the spatial learning memory ability of rats,but the combination of L-band and C-band exposure,or L-band exposure alone could alleviate anxiety in rats.The effects on hippocampal dendritic spine structure in rats were frequencydependent.