Ryan B M, Mallett E, Johnson T R, Gauger J R, McCormick D L
Life Sciences Department, IIT Research Institute, Chicago, Illinois 60616, USA.
Teratology. 1996 Aug;54(2):73-83. doi: 10.1002/(SICI)1096-9926(199606)54:2<73::AID-TERA3>3.0.CO;2-5.
Considerable public concern has developed regarding possible adverse reproductive outcomes resulting from exposure to power frequency magnetic fields (MF). To identify possible effects of MF exposure on fetal development, timed-pregnant female Sprague-Dawley rats (55/ group) received continuous exposure to linearly polarized, transient-free 60 Hz MF at field strengths of 0 Gauss (G; sham control), 0.02 G, 2 G, or 10 G, or intermittent (1 hr on/1 hr off) exposure to 10 G fields. Dams received MF or sham exposures for 18.5 hr/day on gestation days 6 through 19. A positive control group of 15 dams received daily oral doses of 85 mg ethylenethiourea (ETU)/kg body weight on gestation days 11, 12, and 13; positive control dams received no MF exposure. Ambient and experimentally generated MF were monitored continuously throughout the study. Experimentally generated MF were within 2% of the target field strengths at all times, and ambient MF to which sham controls were exposed did not exceed 0.7 mG at any point in the study. No evidence of maternal toxicity was identified in any MF-exposed dam; mean maternal body weight and organ weights in groups exposed to MF did not differ from those in sham controls. Comparisons of fetal viability and body weight demonstrated no biologically significant differences between MF-exposed groups and sham controls. Similarly, a battery of gross external, visceral, skeletal, and cephalic examinations demonstrated no significant differences in the incidence of fetal malformations or anomalies in MF-exposed groups vs. sham controls. By contrast, 100% of the fetuses in the positive control group treated with ETU demonstrated malformations and reduced body weight. Exposure of pregnant Sprague-Dawley rats to 60 Hz at field strengths up to 10 G during gestation days 6-19 did not produce biologically significant effects in either dams or fetuses. These results do not support the hypothesis that exposure to pure, linearly polarized 60 Hz MF is a significant risk factor for the developing fetus.
公众对因接触工频磁场（MF）可能导致的不良生殖结局已产生了相当大的关注。为了确定MF暴露对胎儿发育的可能影响，将定时怀孕的雌性斯普拉格-道利大鼠（每组55只）连续暴露于场强为0高斯（G；假对照）、0.02 G、2 G或10 G的线性极化、无瞬变的60 Hz MF中，或将其间歇性（开1小时/关1小时）暴露于10 G场中。在妊娠第6天至19天，母鼠每天接受18.5小时的MF或假暴露。15只母鼠组成的阳性对照组在妊娠第11、12和13天每天口服85毫克乙撑硫脲（ETU）/千克体重；阳性对照母鼠未接受MF暴露。在整个研究过程中持续监测环境和实验产生的MF。实验产生的MF在任何时候都在目标场强的2%以内，并且在研究的任何时间点，假对照所暴露的环境MF都不超过0.7毫高斯。在任何暴露于MF的母鼠中均未发现母体毒性的证据；暴露于MF的组中母鼠的平均体重和器官重量与假对照组相比没有差异。胎儿活力和体重的比较表明，暴露于MF的组与假对照组之间在生物学上没有显著差异。同样，一系列的大体外部、内脏、骨骼和头部检查表明，暴露于MF的组与假对照组相比，胎儿畸形或异常的发生率没有显著差异。相比之下，用ETU治疗的阳性对照组中100%的胎儿出现畸形且体重减轻。在妊娠第6 - 19天，将怀孕的斯普拉格-道利大鼠暴露于场强高达10 G的60 Hz中，对母鼠或胎儿均未产生生物学上的显著影响。这些结果不支持以下假设，即暴露于纯的、线性极化的60 Hz MF是发育中胎儿的一个重要风险因素。
