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

[900MHzの電磁界へのばく露はラットのmkp-1/ERK経路を活性化し、血液脳関門の損傷および認知障害を引き起こす] med./bio.

Exposure to 900 MHz electromagnetic fields activates the mkp-1/ERK pathway and causes blood-brain barrier damage and cognitive impairment in rats.

掲載誌: Brain Res 2015; 1601: 92-101

この研究は、SDラット(n=108)に900MHzの電磁界EMF;1mW/cm2、全身平均SARが0.0162W/kg、頭部の局所SARが2W/kg)のばく露を、1日3時間、14日間または28日間与えた後、さまざまな組織学的検査およびモーリス水迷路試験を行った。その結果、28日ばく露群では、14日ばく露群および無ばく露群に比べ、空間記憶の低下が観察された;また28日ばく露群では、細胞浮腫および神経細胞オルガネラの変性血液脳関門透過性の損傷が見られた、と報告している。

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研究目的(著者による)

The effects of exposure of rats to a 900 MHz electromagnetic field on the spatial memory, neuronal and blood brain barrier damage and the potential underlying mechanisms of action should be investigated.

詳細情報

108 rats were divided into 3 groups (n=36 each): 1) sham exposure, 2) exposure to the magnetic field for 14 days and 3) 28 days. In each group, 3 rats were used for electron microscopy, 6 were used for immunohistochemistry, 12 for the evans blue assay, 6 for Western blot and 9 for the Morris water maze.
Heme oxygenase-1 (HO-1) is a marker for oxidative stress. MAPK phosphatase-1 (mkp-1) regulates the activity and expression of ERK 1 and 2. The authors hypothesized that the mkp-1/ERK pathway is potentially involved in the regulation of HO-1, the damaging of the blood brain barrier and resulting cognitive impairments.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 900 MHz
ばく露時間: continuous for 3 h/day for 14 days
  • 電力: 2 W peak (output power)
  • 電力密度: 1 mW/cm² (near the head)
  • SAR: 0.016 W/g (determined in phantom)
  • SAR: 2 W/g (in the head, determined in phantom)
ばく露2: 900 MHz
ばく露時間: continuous for 3 h/day for 28 days
  • 電力: 2 W peak (output power)
  • 電力密度: 1 mW/cm² (near the head)
  • SAR: 0.016 W/g (determined in phantom)
  • SAR: 2 W/g (in the head, determined in phantom)

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 3 h/day for 14 days
ばく露装置
ばく露の発生源/構造
  • モノポール
Distance between exposed object and exposure source 1 m
ばく露装置の詳細 four rats were exposed simultaneously in an immobilization apparatus with their heads towards the antenna at a distance of at least 1 m; the propagation direction of the signal was in the direction of the long-axis of the rats; the position of the rats during exposure on each day was altered
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電力 2 W peak - - output power
電力密度 1 mW/cm² - 測定値 - near the head
SAR 0.016 W/g - 測定値および計算値 whole body determined in phantom
SAR 2 W/g - 測定値および計算値 partial body in the head, determined in phantom

ばく露2

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 3 h/day for 28 days
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
電力 2 W peak - - output power
電力密度 1 mW/cm² - 測定値 - near the head
SAR 0.016 W/g - 測定値および計算値 whole body determined in phantom
SAR 2 W/g - 測定値および計算値 partial body in the head, determined in phantom

Reference articles

  • Hao D et al. (2013): [ラットの空間学習及び記憶に対する長期的な電磁界ばく露の影響]
  • Tu WZ et al. (2012): [ラッの後根神経節ニューロンのP2X3受容体が仲介する神経因性慢性疼痛に対する電気的鍼治療の鎮痛効果]
  • Odaci E et al. (2008): [ラット歯状回に対する900 MHz電磁界の出生前ばく露の影響:立体学的および組織病理学的研究]

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 spatial memory was significantly impaired after 28 days of exposure (group 3) compared to the 14-day exposure group (group 2) and sham exposure.
The neuronal ultrastructure was changed in groups 2 and 3 compared to sham exposure with edema between neurons and blood vessels. Group 3 showed additional swollen or missing organelles and cytoplasmic vacuolization in neurons.
The level of HO-1 was significantly higher in both exposure groups compared to the sham exposure and in group 3 compared to group 2.
In immunohistochemical analysis, a significant higher level of albumin was found in group 3 in the hippocampus and cortex compared to group 2 and sham exposure, but albumin could also be detected in neurons of group 2. Additionally, a significant higher amount of evans blue could be detected in groups 2 and 3 compared to sham exposure. The mkp-1 expression was significantly up-regulated and ERK phosphorylation significantly reduced in group 3 compared to the sham exposure.
The authors conclude, that exposure of rats to a 900 MHz electromagnetic field could impair the spatial memory and damage the blood brain barrier and that the mkp-1/ERK signaling pathway may be involved in this process.

研究の種別:

研究助成

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