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

[2.45 GHz電磁界へのばく露はラットの海馬におけるHSP関連のストレス応答を生じる] med./bio.

Exposure to 2.45 GHz electromagnetic fields elicits an HSP-related stress response in rat hippocampus

掲載誌: Brain Res Bull 2012; 88 (4): 371-378

この実験研究は、電磁界ストレス応答を引き起こしうる環境刺激であるか否かを判断するために、敏感な標的組織として海馬を取り上げて、電磁界ばく露後の海馬におけるストレス関連の遺伝子およびタンパク質発現の変化を調べた。成獣雄Sprague-Dawley ラット(2月齢)を無作為にばく露群と擬似ばく露群に分けた。両群の匹数はcDNAマイクロアッセイに12匹、免疫組織化学検査に6匹である。その他にRT-PCRとウェスタンブロット用にそれぞれ6匹ずつの7群(擬似ばく露群、ばく露群でばく露終了0、0.5、1、3、6、12時間後に検査する群)を用いた。ばく露擬似ばく露時にはラット拘束して、ばく露は2.45 GHz、SAR 6 W/kg(FDTD法で算出とあるが詳述なし)、ばく露時間20分間であった。その結果、2048個の候補遺伝子のうち、上方調節23個、下方調節18個が同定された;そのうちHSP27、HSP70の海馬でのタンパク質発現レベル上昇が顕著であった;このふたつのHSPの遺伝子およびタンパク質発現プロファイルはRT-PCRとウェスタンブロット法でも確認されたことなどを報告している。

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研究目的(acc. to editor)

To study the effects of radiofrequency electromagnetic field exposure on stress-related gene expression in the rat hippocampus.

詳細情報

Rats were divided into the following groups: 1) sham exposure group (for microarray analysis; n=12; investigated 3 h after exposure), 2) exposure group (for microarray analysis; n=12; investigated 3 h after exposure), 3) exposure group (for immunohistochemistry; n=6; investigated 3 h after exposure), 4) sham exposure (for RT-PCR and Western blot; n=6), 5-10) exposure groups, investigated 0 h, 0.5 h, 1 h, 3 h, 6 h, and 12 h after exposure (for RT-PCR and Western blot; n=5 or 6 (contradictory statements)).
RNA was pooled from six exposed/sham exposed hippocampi.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 2.45 GHz
Modulation type: pulsed
ばく露時間: continuous for 20 min

ばく露1

主たる特性
周波数 2.45 GHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 20 min
Modulation
Modulation type pulsed
Pulse width 2 ms
Packets per second 500
ばく露装置
ばく露の発生源/構造
Distance between exposed object and exposure source 90 cm
ばく露装置の詳細 radiation trasmitted horizontally from a rectangular horn antenna; using a reflector the radiation was redirected vertically to the exposure chamber; rats placed in Plexiglas restrainers to avoid head movement; restrainers placed inside anechoic chambers at a constant temperature of 25 - 26°C
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電力密度 65 mW/cm² average over time - - -
SAR 6 W/kg - - - -

Reference articles

  • Hao Y et al. (2010): [STAT3シグナル伝達経路は2.45 GHz電磁界に誘導されるミクログリア活性化に関与する]

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:
  • ばく露後

研究の主なアウトカム(著者による)

Out of 2048 genes, 23 genes were upregulated and 18 were downregulated. Seven stress-associated heat shock proteins or chaperones were found among the differentially expressed genes, including HSP27 and HSP70 with a markedly increased expression.
The data from immunohistochemistry revealed that the electromagnetic field exposure caused an intensive staining for HSP27 and HSP70 in the hippocampus, especially in the pyramidal cells of cornu ammonis 3 (CA3) and granular cells of dentate gyrus. The gene expression and protein expression profiles of HSP27 and HSP70 were confirmed by RT-PCR and Western blot. Early and long-lasting expression of HSP27 and HSP70 was detected up to 12 h after exposure and exhibited differential expression patterns after exposure.
The authors conclude that the data provide evidence that exposure to electromagnetic fields elicits a stress response in the rat hippocampus. Thermal effects might have contributed to the HSP-related stress response in the rat hippocampus after radiofrequency exposure.

研究の種別:

研究助成

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