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

[ラット脳のピクロトキシンモデルにおける900MHzのGSM放射への急性ばく露後の神経毒性バイオマーカc-fosおよびGFAPの研究] med./bio.

A study of neurotoxic biomarkers, c-fos and GFAP after acute exposure to GSM radiation at 900MHz in the picrotoxin model of rat brains.

掲載誌: Neurotoxicology 2011; 32 (4): 478-494

この研究は、正常なラット発作傾向のあるラットを用いて、GSM携帯電話からのマイクロ波へのばく露による急性影響を調べた。ばく露には、携帯電話放射と同様の強度の900MHz電磁放射を用いた。発作傾向のあるラットは、ピクロトキシンの急性亜痙攣用量の投与により実験的に作成した。72匹の成獣のオスのSprague-Dawleyラットを、(ピクロトキシン投与あり、なし)×(2時間の電磁放射ばく露擬似ばく露)×(影響評価のタイミングがばく露終了から90分後、24時間後、72時後)の合計12群(n = 6)に分けた。影響評価は、関連する解剖学的領域の免疫化学的検査試験を行い、ばく露後90分および24時間でのニューロンマーカc-fosの誘導、およびばく露後72時間でのグリア線維性酸性タンパク質(GFAP)の誘導を測定した。実験装置での吸収電力測定およびFDTD法による数値計算から算出された脳組織平均SAR値は、正常ラットで1.38 W / kg、ピクロトキシン処理ラットで1.45W / kgであった。その結果、ばく露を受けたピクロトキシン処理ラットでは、ばく露後90分で、新皮質と古皮質でのc-fos発現レベルが高く、また海馬の活性が低かった;ばく露を受けたピクロトキシン処理ラットでは、ばく露後24時間で、大脳辺縁系皮質領域を除くほとんどの脳領域でニューロン活性が増加を示した;ばく露を受けたピクロトキシン処理ラットでは、ばく露後72時間においても、ばく露の影響は新皮質歯状回、およびCA3で依然として明らかであったが、毛様体および嗅内皮質では有意な活性低下が見られた;総括すると、脳組織に対する非熱レベル電磁放射とピクロトキシン毒性作用の複合ストレスが、神経毒性ニューロンマーカおよびグリアマーカ誘導を引き起こしたことが示された、と報告している。

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研究目的(著者による)

To study a time-course description of effects after acute microwave exposure in the rat brain by measuring 1) the neuronal activation using the c-fos expression and 2) glial reactivity as an indicator of parallel neuronal damage in seizure-related rat model.

詳細情報

Rats were made seizure-prone by injection of a subconvulsive dose of the GABA antagonist picrotoxin.
72 adult male rats were divided into 12 groups: 1) picrotoxin treated (to induce seizure proneness), exposed for 2 h and investigated after 90 min., 2) picrotoxin treated, sham-exposed for 2 h and investigated after 90 min., 3) no picrotoxin administration, exposed for 2 h and investigated after 90 min., 4) no picrotoxin administration, sham-exposed for 2 h and investigated after 90 min., 5) picrotoxin treated, exposed for 2 h and investigated after 24 h, 6) picrotoxin treated, sham-exposed for 2 h and investigated after 24 h, 7) no picrotoxin administration, exposed for 2 h and investigated after 24 h, 8) no picrotoxin administration, sham-exposed for 2 h and investigated after 24 h, 9) picrotoxin treated, exposed for 2 h and investigated after three days, 10) picrotoxin treated, sham-exposed for 2 h and investigated after three days, 11) no picrotoxin administration, exposed for 2h and investigated after three days, 12) no picrotoxin administration, sham-exposed for 2 h and investigated after three days.

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: continuous for 2 h
  • 電力: 1 W (output power)
  • 電力: 192.67 mW maximum (178.37 - 192.67 mW mean absorbed power with PT)
  • 電力: 202.33 mW maximum (189.41 - 202.33 mW mean absorbed power without PT)
  • SAR: 1.44 W/kg mean (brain) (1.32 - 1.44 W/kg with PT)
  • SAR: 1.38 W/kg mean (brain) (1.35 - 1.38 W/kg without PT)
  • SAR: 1.62 W/kg peak (1 g) (1.48 - 1.62 W/kg in the brain with PT)
  • SAR: 1.55 W/kg peak (1 g) (1.52 - 1.55 W/kg in the brain without PT)
  • SAR: 0.81 W/kg mean (whole body) (0.74 - 0.81 W/kg with PT)
  • SAR: 0.78 W/kg mean (whole body) (0.76 - 0.78 W/kg without PT)
  • SAR: 4.47 W/kg peak (1 g) (4.09 - 4.47 W/kg in the body with PT)
  • SAR: 4.28 W/kg peak (1 g) (4.19 - 4.28 W/kg in the body without PT)

General information

rats were treated in 12 groups: i) rats injected with picrotoxin (PT) 5 min before the experiment and immobilized in methacrylate tubes with exposure to GSM for 2 h; rats studied 90 min after end of immobilization ii) rats injected with picrotoxin (PT) 5 min before the experiment and immobilized in methacrylate tubes without GSM exposure for 2 h; rats studied 90 min after end of immobilization ii) rats injected with vehicle (no PT) 5 min before the experiment and immobilized in methacrylate tubes with exposure to GSM for 2 h; rats studied 90 min after end of immobilization iv) rats injected with vehicle (no PT) 5 min before the experiment and immobilized in methacrylate tubes without GSM exposure for 2 h; rats studied 90 min after end of immobilization v) as i) but rats studied 24 h after end of immobilization vi) as ii) but rats studied 24 h after end of immobilization vii) as iii) but rats studied 24 h after end of immobilization viii) as iv) but rats studied 24 h after end of immobilization ix) as i) but rats studied 3 days after end of immobilization x) as ii) but rats studied 3 days after end of immobilization xi) as iii) but rats studied 3 days after end of immobilization xii) as iv) but rats studied 3 days after end of immobilization

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 2 h
Modulation
Modulation type pulsed
Additional information

GSM

ばく露装置
ばく露の発生源/構造
  • antenna
ばく露装置の詳細 methacrylate tubes with immobilized rats placed in a 150 cm x 46 cm x 70 cm radiation cage with an incorporated transmission antenna
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電力 1 W - - - output power
電力 192.67 mW maximum - - 178.37 - 192.67 mW mean absorbed power with PT
電力 202.33 mW maximum - - 189.41 - 202.33 mW mean absorbed power without PT
SAR 1.44 W/kg mean 推定値 brain 1.32 - 1.44 W/kg with PT
SAR 1.38 W/kg mean 推定値 brain 1.35 - 1.38 W/kg without PT
SAR 1.62 W/kg peak 推定値 1 g 1.48 - 1.62 W/kg in the brain with PT
SAR 1.55 W/kg peak 推定値 1 g 1.52 - 1.55 W/kg in the brain without PT
SAR 0.81 W/kg mean 推定値 whole body 0.74 - 0.81 W/kg with PT
SAR 0.78 W/kg mean 推定値 whole body 0.76 - 0.78 W/kg without PT
SAR 4.47 W/kg peak 推定値 1 g 4.09 - 4.47 W/kg in the body with PT
SAR 4.28 W/kg peak 推定値 1 g 4.19 - 4.28 W/kg in the body without PT

Reference articles

  • Lopez-Martin E et al. (2009): [パルス変調GSM放射の作用はピクロトキシン誘発発作傾向のあるラットモデルの皮質および皮質下領域における脳活動およびc-Fos発現における限局的変化を増加させる]
  • Lopez-Martin F et al. (2008): [900MHzのGSM定在波の小動物での吸収電力の測定のための実験装置:Picrotoxin処理されたラットへの適用例]
  • Lopez-Martin E et al. (2006): [痙攣閾値下の用量のピクロトキシンで前処置されたラットにおいてGSM放射は発作を誘発し、脳のc-Fos陽性を増加させる]
  • Huber R et al. (2003): [ヒトでのラジオ周波電磁界ばく露:脳でのSAR分布の推定、睡眠と心拍への影響]
  • Fritze K et al. (1997): [ラット脳のゲノム反応に対する携帯電話通信マイクロ波ばく露によるグローバルシステムの影響]

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)

The data revealed that c-fos expression and glial markers were triggered by the combined stress of non-thermal mobile phone exposure and the toxic effect of picrotoxin on cerebral tissues:
90 minutes after exposure high levels of c-fos expression were recorded in the neocortex and paleocortex along with low hippocampus activation in picrotoxin treated animals. Most brain areas, except the piriform cortex, showed important increases in neuronal activation 24 h after exposure and picrotoxin administration. Three days after picrotoxin treatment, exposure effects were still apparent in the neocortex, and the hippocampal sturctures (dentate gyrus and CA3), but a significant decrease in activity was found in the palaeocortex structures (piriform cortex and entorhinal cortex). During this time, glial reactivity increased in brain regions of irradiated, picrotoxin-treated animals.
The findings suggest the need for further examination of the effects of mobile telephone exposure on epileptic patients.

研究の種別:

研究助成

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