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

[ラットにおける血漿コルチコステロン濃度の上昇および海馬グルココルチコイド受容体の転座：継続的な低電力密度のマイクロ波ばく露後の認知機能障害の潜在的なメカニズム] med./bio.

Elevation of plasma corticosterone levels and hippocampal glucocorticoid receptor translocation in rats: a potential mechanism for cognition impairment following chronic low-power-density microwave exposure

著者: Li M, Wang Y, Zhang Y, Zhou Z, Yu Z
掲載誌: J Radiat Res 2008; 49 (2): 163-170
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この研究は、低電力密度マイクロ波（MW）電磁界への慢性ばく露による認知障害に糖質コルチコイド（GC）が関与するか否かを、ラット実験で調べた。Wistarラットに、平均電力密度1 mW / cm2の2.45 GHz MWパルス電磁界のばく露を、毎日3時間、最大30日間与えた。その結果、MWばく露を受けたラットでは、空間学習および記憶タスクの遂行に大きな障害が見られた；MWばく露は、血漿コルチコステロンのレベルを増加させることで、海馬でのGC受容体（GR）の核転座およびアポトーシスを増加させることが示された；しかし、MWばく露と同時にGR拮抗薬RU486を投与した場合、認知の障害および神経細胞の喪失が部分的に回復された；これらの知見は、GCが低電力密度MWの長期ばく露によって誘発される認知障害に関与する可能性を示した、と報告している。

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研究目的（著者による）

To study whether glucocorticoids take part in cognition impairment after exposure to chronic low-power-density microwave fields.

詳細情報

56 rats were divided into four groups (each group = 14 rats): 1) exposure group, 2) exposure + RU486 treatment, 3) exposure + saline solution treatment, and 4) sham exposure group. 30 minutes before the first exposure, rats were subcutaneously injected with either the glucocorticoid receptor antagonist RU486 (120 mg/kg) or physiological saline. Rats were then given repeated injections every fifth day.
Four animals of each group were used for apoptosis investigation, five animals were used for behavioural tests, and five animals were used for corticosterone level determination.

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 3 hr/day for up to 30 days
  • 電力密度: 1 mW/cm² spatial average
  • SAR: 0.2 W/kg average over time (whole body)
  • SAR: 0.7 W/kg average over time (brain)

General information

animals were divided into four groups: i) MW exposure ii) MW exposure + 120 mg/kg RU486 iii) MW exposure + 1 ml/kg physiological saline iv) sham exposure

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 3 hr/day for up to 30 days
Modulation
Modulation type pulsed
Pulse width 10 µs
Packets per second 800
ばく露装置
ばく露の発生源／構造
ばく露装置の詳細 cylindrical waveguide system where individual cylindrical exposure tubes are connected through a power divider network to the single MW source; each tube comprises a section of the circular waveguide constructed of galvanized wire screen in which a circularly polarized TE11-mode field configuration is excited; the tube contains a 23.6 cm long plastic chamber with a diameter of 17.6 cm
Sham exposure A sham exposure was conducted.
パラメータ
測定量 値 種別 Method Mass 備考
電力密度 1 mW/cm² spatial average - - -
SAR 0.2 W/kg average over time 測定値 whole body -
SAR 0.7 W/kg average over time 計算値 brain -

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:
  • ばく露後

研究の主なアウトカム（著者による）

The data showed that microwave exposed rats had significant deficits in spatial learning and memory performance. The data analysis showed that microwave exposure induced a significant prolongation in escape latency on the fourth, fifth and sixth day and goal quadrant dwell-time on day seven was significantly reduced in microwave exposed rats.
Microwave exposure increased levels of plasma corticosterone, glucocorticoid receptor nuclear translocation (microwave exposure caused a decrease in the cytoplasmic signal and an increase in the nuclear signal compared to sham exposed control) and apoptosis in the hippocampus.
However, co-exposure of the glucocorticoid receptor antagonist RU486 with microwave exposure partially reversed the cognitive impairment and neuronal changes.
These findings indicate that glucocorticoid receptors might contribute to the cognition deficit induced by chronic low-power-density microwave exposure.

研究の種別:

研究助成

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