研究のタイプ: 医学/生物学の研究 (experimental study)

[20または60kHzの磁界ばく露を受けたラットに催奇形性影響見られず] med./bio.

Lack of teratological effects in rats exposed to 20 or 60 kHz magnetic fields.

掲載誌: Birth Defects Res B Dev Reprod Toxicol 2011; 92 (5): 469-477

この研究は、中間周波(300 Hz - 100 kHz)の磁界MF)を発生する誘導加熱(IH)調理器に腹部が接近する調理者での生殖および発達への影響についての懸念を背景に、ラットを用いたばく露実験を行った。妊娠したCrl:CD(SD)ラットをMFばく露群と擬似ばく露対照群(各n = 25)に分け、それぞれは器官形成期に、20 kHz、0.2 mT(rms)または60 kHz、0.1 mT(rms)の正弦波MFのばく露(または擬似ばく露)を1日22時間受けた。妊娠20日目に、胎仔の奇形を検査した。すべての奇形評価はブラインド方式で実施し、実験結果の一貫性を確認するために、それぞれの周波数で同じ実験を2回行った。その結果、臨床徴候、肉眼的病理学的検査項目、または着床消失数に、ばく露に関連した変化は見られなかった;生産胎仔および低体重胎仔の数、および胎仔の外的奇形、内臓および骨格奇形発生率にMFばく露群と擬似ばく露群の間での有意差はなかった;一部の胎仔で、性比骨格および骨化の変化が孤立的に見られたが、そのような変化は、重複実験では再現されず、特定の周波数に共通でもなかった;総括すると、ラット器官形成期におけるMFばく露は、実験条件下で有意な再現性のある催奇形性を示さなかった、と報告している。

The detailed summary of this article is not available in your language or incomplete. Would you like to see a complete translation of the summary? Then please contact us →

研究目的(著者による)

To study whether 20 and 60 kHz intermediate magnetic field exposures have embryotoxic, fetotoxic, and/or teratogenic potential in rats.

詳細情報

Pregnant rats (25 per group) were exposed to a 20 kHz or 60 kHz sinusoidal magnetic field or sham exposed for 22 hr/day during organogenesis, and their fetuses were examined for malformations on gestation day 20. Experiments were duplicated for each frequency to confirm consistency of data.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 20 kHz
ばく露時間: continuous for 22 h/day from day 7 to day 17 of gestation
ばく露2: 60 kHz
ばく露時間: continuous for 22 h/day from day 7 to day 17 of gestation

ばく露1

主たる特性
周波数 20 kHz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 22 h/day from day 7 to day 17 of gestation
ばく露装置
ばく露の発生源/構造
ばく露装置の詳細 two Merritt-type four square coil systems positioned 37.4 m apart; coils layered horizontally in a wooden structure with a side length of 150 cm and a height of 161 cm; coils spaced at 60, 41 and 60 cm; coils with 26:11:11:26 turns of wire; 3 racks placed inside the coil system to house 36 rat cages, 12 on each rack in a 3-row by 4-column layout; one rat per cage; 100 cm x 100 cm x 100 cm exposure area in the center of the coil system with MF variability less than 3%; structural outer walls, high roof and deep basement, contained steel-bar reinforcement grids to reduce MF leakage to the outside
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.2 mT effective value 測定値 - -

ばく露2

主たる特性
周波数 60 kHz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 22 h/day from day 7 to day 17 of gestation
ばく露装置
ばく露の発生源/構造
ばく露装置の詳細 same setup as in Exposure 1, but coils with 7:3:3:7 windings
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.1 mT effective value 測定値 - -

ばく露を受けた生物:

方法 影響評価項目/測定パラメータ/方法

研究対象とした生物試料:
調査の時期:
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

No exposure-related alterations were revealed in clinical signs, gross pathology, or number of implantation losses. The number of live fetuses and low-body-weight fetuses as well as the incidence of external, visceral, and skeletal malformations in the fetuses did not indicate significant differences between exposed and sham exposed groups. Although some fetuses showed isolated changes in sex ratio and skeletal variation and ossification, such changes were neither reproduced in duplicate experiments nor were they common to specific field frequencies. No magnetic field frequency-specific response was manifested in any of the endpoints
The authors conclude that exposure of rats to magnetic fields during organogenesis did not show a significant reproducible teratogenicity under these experimental conditions. The data do not support the hypothesis that an intermediate frequency magnetic field exposure after implantation carries a significant risk for mammalian fetuses development.

研究の種別:

研究助成

関連論文