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

[雄ラットの甲状腺ホルモンと行動を変える変調2450 MHzマイクロ波放射の慢性的な非熱ばく露] med./bio.

Chronic non-thermal exposure of modulated 2450 MHz microwave radiation alters thyroid hormones and behavior of male rats

著者: Sinha RK
掲載誌: Int J Radiat Biol 2008; 84 (6): 505-513
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目的は、オスラットの甲状腺ホルモンと行動に対する漏れマイクロ波放射の影響を解析することでる。【方法】2グループ（ばく露と対照）のオスラットを実験に用い、RIA法で3, 5, 3´トリヨードチロニン (T3)、サイロキシン (T4)、TSHを求めた。行動の評価は、オープン場（OF）とメーズ装置（EPM）で行った。【結果】慢性的にマイクロ波を照射後、ラットは16日目と21日目に過度に活発になり、また攻撃的になった。OFでの行動変化を分析し、動かなくなり、立ち上がったり、歩行などの行動が対照群とは異なることがわかった（p<0.05）。EPMでは、照射後、11、16、21日目で、ラットはオープン部で過ごすのが減少し中央部で過ごす時間が多くなった。また対照と比べて、行動変化のパラメータが、血液中のホルモンレベルの変化と同じように関連する傾向が見られた。T3（16日、21日で減少）、T4（21日で増加）。【結論】低エネルギーのマイクロ波放射は、対照群と比較するばく露群では甲状腺ホルモンレベル、感情反応に変化を及ぼすので、有害であることが言えるかもしれない。

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研究目的（著者による）

To determine the effects of chronic exposure to low energy 2450 MHz nonthermal microwave irradiation on thyroid hormones and to analyze how these changes in thyroid hormones, if any, affect the reactiveness and emotional behavior of rats.

詳細情報

Twenty male rats of 4-5 weeks of age were analyzed. Blood was taken from the tails of each rat on the 1st, 6th, 11th, 16th and 21st day immediately after two hours irradiation or sham exposure.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 2,450 MHz
Modulation type: pulsed
ばく露時間: repeated daily exposure, 2 h/day, for up to 21 days
  • 電力: 12.5 mW
  • 電力密度: 16.5 µW/cm² (at the bottom of the holder)
  • SAR: 3.6 µW/g average over mass (whole body) (parallel to the E plane)
  • SAR: 0.98 µW/g average over mass (whole body) (parallel to the H plane)

ばく露1

主たる特性
周波数 2,450 MHz
タイプ
  • electromagnetic field
ばく露時間 repeated daily exposure, 2 h/day, for up to 21 days
Modulation
Modulation type pulsed
Repetition frequency 1 kHz
Pulse type rectangular
ばく露装置
ばく露の発生源／構造
Distance between exposed object and exposure source 23 cm
チャンバの詳細 The flair angle of the antenna was 9.6° in both the electric (E) and the magnetic (H) plane. The distance of the antenna from the top of the animal holder was 23 cm. The 3 dB points for both H and E planes were calculated and used in the design of the animal holder for five rats that consisted of a Perspex box with five compartments on a 10-cm Styrofoam base of 29.87 x 25.3 cm. The internal partitioning was made of pine wood due to its low dielectric constant and loss tangent. All external and internal walls, excluding the base were perforated at uniform distances to make the holder anechoic. An absorber made of carbon coated Styrofoam with cones on its surface was placed below the holder to reduce reflected radiation.
ばく露装置の詳細 The long axis was positioned parallel to the E-field for two of the compartments and parallel to the H-field for the other three. Rats were not restrained and were free to change their posture within the cage. They were rotated daily from one chamber to the next chamber in succession.
Sham exposure A sham exposure was conducted.
Additional information Tests and analyses were performed on the 1st, 6th, 11th, 16th and 21st day of the experiment immediately after RF or sham exposure.
パラメータ
測定量 値 種別 Method Mass 備考
電力 12.5 mW - 推定値 - -
電力密度 16.5 µW/cm² - 計算値 - at the bottom of the holder
SAR 3.6 µW/g average over mass 計算値 whole body parallel to the E plane
SAR 0.98 µW/g average over mass 計算値 whole body parallel to the H plane
測定および計算の詳細

The maximum power output was measured using a power sensor and power meter. The power transmitted by the antenna was estimated. The average SARs parallel to the E plane and to the H plane were calculated by simple empirical equations [Gandhi et al., 1977 and Gandhi, 1974, respectively]. The phenomenon of polarization was studied theoretically and experimentally by previously described methods [Bachmann et al., 2005 and Hinrikus et al., 2005].

Reference articles

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:
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）

Concerning behavioral changes in open field, significant increase in mobility, rearing, and central/peripherial ambulation were found in exposed rats on the 16th and 21st days of exposure. In elevated plus maze, rats showed increased activity with decreased time spent in the open arm and more time spent in the center on the 11th, 16th and 21st day after irradiation. The changes in behavioral parameters were accompanied by decreased levels of triiodothyronine on the 16th day and 21st day and increased levels of thyroxine on the 21st day of exposure.
The authors conclude that low energy microwave irradiation may be harmful as it is sufficient to alter the levels of thyroid hormones as well as the emotional reactivity of rats.

研究の種別:

研究助成

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