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

[ラットのDMBA誘発腫瘍に対する900 MHzGSM無線通信シグナルの影響] med./bio.

Effects of 900 MHz GSM wireless communication signals on DMBA-induced mammary tumors in rats

著者: Yu D, Shen Y, Kuster N, Fu Y, Chiang H
掲載誌: Radiat Res 2006; 165 (2): 174-180
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この研究は、900 MHzのGSM無線通信信号へのばく露が、低用量DMBAにより誘発された乳腺腫瘍の発症および増殖を増強するかどうかを調べた。500匹の雌Sprague-Dawleyラットを35 mg / kg DMBAの単回投与で処理した後、ブラインド法で5群に分けた：1つのケージ対照群、4つのばく露群（3つのGSMばく露群（SARが4.0、1.33、0.44 W / kg）と1つの擬似ばく露群（SARが0 W / kg））。ばく露は、DMBA投与の翌日から開始し、1日4時間、週5日、26週間継続した。毎週、ラットの体重測定、腫瘍の存在を確認するための触診を行い、ばく露終了直後に屠殺して、すべての乳腺を組織学的に検査した。その結果、擬似ばく露群とGSMばく露群の間に体重の有意差はなかった；擬似ばく露群とGSMばく露群の間に、全乳腺腫瘍の発生率、腫瘍発症までの潜時、腫瘍の多様性、または腫瘍サイズに有意差はなかった；擬似ばく露群に比べ、最低レベルばく露群（0.44 W / kg）では乳腺腺がんの発生率が低い傾向性が見られた（P = 0.058）；腺がんの高めの発生率が、ばく露の15週目から26週目までの4.0 W / kg群で見られ、特に19週目で高かったが、どちらの傾向も統計学的に有意ではなかった；したがって、この研究は、GSMマイクロ波ばく露がラットの乳腺腫瘍発生を促進するという証拠を提供していない、と報告している。

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研究目的（著者による）

To study whether exposure to 900 MHz GSM wireless communication signals enhances mammary tumor development and growth induced by low-dose DMBA.

詳細情報

500 rats were treated with a single dose of 35 mg/kg DMBA and exposure started on the day after DMBA administration.
This study was a parallel project to one part of the PERFORM-A program (International EMF project launched by WHO).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 900 MHz
Modulation type: pulsed
ばく露時間: repeated daily exposure, 4 h/day, 5 days/week, for 26 weeks
  • SAR: 4 W/kg average over mass (whole body)
  • SAR: 1.33 W/kg average over mass (whole body)
  • SAR: 0.44 W/kg average over mass (whole body)

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 repeated daily exposure, 4 h/day, 5 days/week, for 26 weeks
Modulation
Modulation type pulsed
Additional information

GSM signal
ばく露装置
ばく露の発生源／構造
チャンバの詳細 The rats where exposed in 12 air-conditioned radial exposure units called wheels, each holding 17 rats. Each week, the exposure positions of each rat on the wheel were rotated one position to the right.
ばく露装置の詳細 The exposure wheel consisted of a circular cascade of 17 sectored waveguides, all of which were excited by one quarter-loop antenna located in the center and providing uniform circular excitation. The rats were restrained in a horizontal position in metal-free polycarbonate tubes inside the waveguide cavity ventilated from the front where the head of the rat was located.
Sham exposure A sham exposure was conducted.
Additional information Exposure was based on a novel concept using H-polarization to provide reasonable homogeneity of exposure for rats of different sizes.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 4 W/kg average over mass - whole body -
SAR 1.33 W/kg average over mass - whole body -
SAR 0.44 W/kg average over mass - whole body -
Additional parameter details

The SARs were assigned to the different exposure groups in blinded fashion (blind study).

測定および計算の詳細

The absolute uncertainty in dosimetry with respect to the positions in the wheel and the variation of the SAR due to the increasing size/weight of rats over the study was ±1.93 dB. The SAR levels for each wheel could be maintained with an uncertainty of less than 1 dB. Detailed dosimetry data will be described in a future paper.

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:
研究対象とした臓器系:
  • breast
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 significant differences in overall mammary tumor incidence, latency to tumor onset, tumor multiplicity, or tumor size were revealed between exposed and sham exposed groups. Additionally, there were no statistically significant differences in body weight.
There was a tendency for reduction of mammary adenocarcinoma incidence in the lowest exposure group (0.44 W/ kg) compared with the sham exposed rats. Additionally, a higher incidence of adenocarcinoma was noticed in the 4.0 W/kg animals from the 15th to 26th weeks. However, neither tendency was statistically significant; thus this study does not provide evidence that GSM microwave exposure promotes mammary tumor development in rats.
There were significant differences between the cage controls and the experimental groups (sham exposure and exposure). Body weight and mammary tumor incidence in the cage control animals were significantly higher than in the sham exposed and exposed rats. The latency to the mammary tumor onset was significantly shorter in the cage control animals than in the other animals.

研究の種別:

研究助成

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