研究のタイプ: 医学/生物学の研究

[ニューリチンは超低周波(50 Hz)電磁界ばく露により引き起こされるマウスの新規オブジェクト連想認知の記憶欠損を反転させる] med./bio.

Neuritin reverses deficits in murine novel object associative recognition memory caused by exposure to extremely low-frequency (50 Hz) electromagnetic fields.

掲載誌: Sci Rep 2015; 5: 11768

この研究は、マウスへの超低周波磁界(ELF MF:50 Hzばく露認知記憶タスクおよび海馬ニューロン形態学に与える影響を調べた。実験では、ELF MF(1 mT、12時間/日)のばく露日数が7-10日間の場合のみ、新規オブジェクト連想認知記憶における欠損および海馬での樹状突起棘密度の低下が見られた;それは一過性で、自発的移動の変化との相関は見られなかった;アデノ随伴ウイルス(AAV)ベクターにより海馬にニューリチン遺伝子を過剰発現させると、ニューリチンレベルおよび樹状突起棘密度が有意に増加した;この増加は、ELF MFによる樹状突起棘密度の低下が原因の認知記憶への影響を防止した、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 mice to a 50 Hz magnetic field on the memory and morphology of neurons in the hippocampus as well as the role of neuritin in this process should be investigated.

詳細情報

Neuritin was recently discovered as an important growth factor for neural development, which promotes neuronal outgrowth and arborization in the brain. Mice with an overexpression of neuritin in the hippocampus were experimentally created (transfection with a viral vector) and used beside normal mice.
Mice were divided into the following groups: exposure of normal mice to a magnetic field with 1) 0.4 mT or 2) 0.6 mT for 7 days and 3) with 1 mT for up to 21 days. Moreover, 4) neuritin-viral-transfected, 5) sham-viral-transfected and 6) saline-transfected mice were exposed to a magnetic field with 1 mT for 10 days. Additional sham exposed control groups were used for each experiment. (remark EMF-Portal: not all group sizes were mentioned, but stated sizes were at least n=10).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 50 Hz
ばく露時間: continuous for 12 h/day for 7 days
ばく露2: 50 Hz
ばく露時間: continuous for 12 h/day for 7 days
ばく露3: 50 Hz
ばく露時間: continuous for 12 h/day for up to 21 days

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 12 h/day for 7 days
ばく露装置
ばく露の発生源/構造
チャンバの詳細 glass cage
ばく露装置の詳細 the glass cage, containing 4 to 5 mice, was placed between the coils; the surfaces of the glass cage were parallel to the force lines of the magnetic field; temperature in glass cage under exposure conditions showed a difference of 0.4 ± 0.1°C compared to the sham exposure
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.4 mT - 測定値 - -

ばく露2

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 12 h/day for 7 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
磁束密度 0.6 mT - 測定値 - -

ばく露3

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 12 h/day for up to 21 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
磁束密度 1 mT - 測定値 - -

Reference articles

  • Ongaro A et al. (2012): [電磁界(EMF)およびアデノシン受容体はヒト骨関節炎の滑膜線維芽細胞におけるプロスタグランジンE2およびサイトカインの放出を変化させる]
  • Varani K et al. (2012): [ラットの脳のアデノシン受容体に対するパルス電磁界ばく露の影響]

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:
  • ばく露後

研究の主なアウトカム(著者による)

Exposure to the magnetic field had no effect on the locomotor activity of mice, whereas the object recognition was significantly impaired in mice exposed to a 1 mT magnetic field for 7 days (group 3) compared to the control group.The dendritic spine density of neurons in the hippocampus was significantly reduced after exposure to a 1 mT magnetic field for 7 or 10 (group 3) days compared to the control group. However, all effects were transient and could not be detected after 14 days anymore.
Mice with an overexpression of neuritin in the hippocampus (group 4) showed no significant differences between the exposure and control groups in dendritic spine density and object recognition after 10 days. Moreover, both parameters were significantly increased compared to mice with normal neuritin protein expression (groups 5 and 6).
The authors conclude that exposure of mice to a 50 Hz magnetic field could impair the memory of mice and alter the morphology of neurons in the hippocampus. However, neuritin could attenuate these effects.

研究の種別:

研究助成

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