妊娠期和哺乳期连续微波辐射对小鼠学习记忆功能的影响与甲状腺激素作用研究

The influence of microwave irradiation during lactation and gestation on the role of thyroid hormone in dysfunction of learning and memory with mice

本研究主要探讨妊娠期间和哺乳期间连续微波辐射,对胎鼠和乳鼠成年后学习记忆功能的影响,以及甲状腺激素T3、T4在其中的作用。实验采用SPF级昆明小鼠48只,分为妊娠期组与哺乳期组,并分别设立对照组,采用30mW/cm2的微波,每天一次性辐射20min,连续辐射,其中对照组只做假辐射处理。妊娠期组自妊娠第1天起辐射至孕鼠分娩,共辐射21天;哺乳期组自出生第1天起连续辐射21天。在辐射第15天时分别取孕鼠和乳鼠血清,采用放免法测血清中游离T3、T4(FT3、FT4)含量,待胎鼠及乳鼠成年后(2月龄)采用Morris水迷宫检测其学习记忆功能。研究发现妊娠期辐射组血清FT4明显低于对照组(p<0.05),而FT3没有显著变化;在定位导航实验中,其寻找平台的潜伏期明显高于对照组(p<0.05),空间搜索实验中在目的象限的停留时间(17.70±7.07s)明显低于对照组(27.14±5.36s)(p<0.05),跨越虚拟平台的次数(0.83±0.41)也明显低于对照组(1.67±0.52)(p<0.01)。哺乳期辐射组血清FT4没有显著变化,而FT3显著降低(p<0.05);在Morris水迷宫实验中,其各项检测指标与对照组相比,没有显著差异。以上结果表明,哺乳期间连续微波辐射能导致乳鼠血清FT3降低,但对乳鼠成年后学习记忆功能无明显影响;妊娠期间连续微波辐射能导致孕鼠血清FT4降低,胎鼠成年后学习记忆功能下降,提示FT4下降可能是微波辐射致胎鼠成年后学习记忆功能下降的因素之一。

It was investigated that the influence of continuous microwave （MW） irradiation during lactation and gestation on the function of learning and memory as well as the role of FT3 and FT4 in this process. 48 SPF KM mice were divided into lactation group, gestation group and control group. All mice were irradiated by MW of 30 mW/cm^2 for 20 min each day except control groups. The gestation group was continuous irradiated until childbirth, about 21 days in total. The lactation group was continuous irradiated for 21 days. The blood serum was obtained on the 15 th day of irradiation and then serum FT3 and FT4 were determined by radioimmunoassay. In the gestation irradiation group, FT3 was not significantly changed while FT4 decreased compare to control group. In Place Navigation Test, the escape latency was prolonged in the gestation irradiation group, while there was not significantly changed in the lactation irradiation group. In Spatial Probe Test, the time spent in target quadrants was much longer and the fre- quency passing through the platform was much more compare to control group. In lactation group, no such change was observed in Morris water maze. The serum FT3 in the lactation irradiation group was decreased while FT4 did not change significantly. The results suggest that continuous MW irradiation during lactation could down regulate serum FT3 level, but could not induce learning and memory function injured. Continuous MW irradiation during gestation could down regulate serum FT4 level and induce learning and memory function injured. The serum TH deeremerit may be one of the main reasons for learning and memory dysfunction induced by MW.