900 MHz微波辐射对大鼠自发活动和血浆褪黑素昼夜节律的影响

Effects of 900 MHz Microwave Radiation on Circadian Rhythm of Locomotor Activity and Plasma Melatonin Level in Rats

[目的]观察900MHz微波辐射对大鼠自发活动及血浆褪黑素水平昼夜节律的影响。[方法]采集30只大鼠24h自发活动数据,利用生物节律单余弦分析软件筛选出24只具有昼夜节律的大鼠,随机分为对照组、光照组、昼夜时点(ZT)3组和ZT15组,每组6只。ZT3组和ZT15组分别在自发活动相位响应曲线的谷值时点(ZT3点)和峰值时点(ZT15点)接受40μW/cm2的900MHz微波辐射,光照组在峰值时点(ZT15点)接受强度为300lx的可见光照射,均1h/d,连续14d;对照组不做任何处理。所有大鼠在微波辐射或光照后进行心脏采血,采血时点分别为ZT3点、ZT7点、ZT11点、ZT15点、ZT19点和ZT23点,测定血浆褪黑素浓度。比较各组大鼠自发活动及褪黑素水平昼夜节律的差异。[结果]与照射前相比,微波辐射组和光照组大鼠自发活动相位响应曲线中值、振幅降低,峰相位时相滞后,差异有统计学意义(P<0.05)。与对照组相比,光照组及ZT3组血浆褪黑素水平相位响应曲线中值、振幅降低,峰相位时相滞后,差异有统计学意义(P<0.05);ZT15组血浆褪黑素水平相位响应曲线振幅降低,峰相位时相滞后,差异有统计学意义(P<0.05)。[结论]40μW/cm2的900MHz微波在自发活动峰值及谷值时点辐射,能够影响大鼠自发活动及血浆褪黑素水平的昼夜节律。

[ Objective ] To investigate the effects of 900 MHz microwave radiation on circadian rhythm of locomotor activities and plasma melatonin levels in rats. [ Methods ] Locomotor activities of 30 rats were measured over a 24 h period, and 24 rats fitting phase response cu.rves （PRCs） of circadian rhythm were selected and randomly divided into control, light, ZT3, and ZT15 groups （6 rats for each group）. The group ZT3 and group ZT15 were exposed to 40μW/cm^2, 900MHz microwave radiation at trough time （ZT3） and peak time （ZT15） of PRCs, respectively, 1 h/d for 14d. The group light was exposed to 3001x visible light at peak time （ZT15）, 1 h/d for 14d. Blood was collected from heart within 48 h after microwave or light exposure （i.e. the first 24h： ZT3, ZT1 I, and ZT19; the second 24 h： ZT7, ZT15, and ZT23）. Locomotor activities and plasma melatonin concentrations were analyzed with cosine model. [ Results] The mesors and amplitudes of locomotor activity curves in group light, group ZT3, and group ZT15 decreased significantly after the exposures （P 〈 0.05）, and the acrophases were delayed （P 〈 0.05）. For group light and group ZT3, the mesors and amplitudes of plasma melatonin concentrations were reduced significantly after ihe radiation （P 〈 0.05）, and the acrophases were delayed （P 〈 0.05）. Compared with the controls, the amplitude of plasma melatonin concentrations of group ZT15 was lowered obviously after radiation, and the acrophase was delayed （P 〈 0.05）. [ Conclusion ] Exposure to 40 μW/cm^2, 900 MHz microwave at trough time and peak time can affect the circadian rhythm of locomotor activity and plasma melatonin level in rats.