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

[卵巣切除ラットの骨形成に対する超低周波磁界への長期ばく露の影響] med./bio.

The effects of long-term exposure to extremely low-frequency magnetic fields on bone formation in ovariectomized rats.

掲載誌: Bioelectromagnetics 2012; 33 (7): 543-549

この実験研究は、60匹の成熟雌Sprague-Dawleyを、超低周波磁界MF:1.5 mT 、50Hz)への長期ばく露(1日当たり4時間、6ヶ月間)の有無と卵巣切除(OVX)の有無を組み合わせた4群(各15匹)に分け、6ヶ月間の処置終了後の骨密度(BMD)、骨形成・骨吸収の諸パラメータ(骨型アルカリフォスファターゼ(BAP)、オステオカルシン、オステオプロトゲリン、N-テロペプタイド)における違いを分析した。その結果、それぞれ処置前の状態に比べ、BMDはOVX+MF無し群で有意に低くなり、OVX + MF群およびOVX無し+ MF群では高くなった。また処置前の4群間のBMDに差異はなかったが、処置後は対照群に比べ、OVX+MF無し群の方が有意に低く、OVX + MF群およびOVX無し+ MF群の方が有意に高かった。また、BAP、オステオカルシン、オステオプロトゲリン、N-テロペプタイドの濃度も、何らかの処置をした3群の方が対照群より有意に変化した。以上から、ELF-MF処置は骨粗鬆症の予防に有効である可能性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 the effects of 50 Hz extremely low frequency magnetic fields on rat bone metabolism.

詳細情報

60 rats were divided into four different groups (each group n=15): 1) unexposed control group; 2) ovariectomized only; 3) non-ovariectomized, exposed; and 4) ovariectomized, exposed. Bilateral ovariectomies were performed four days before the beginning of the experiments.

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 4 h/day during 6 months, starting on the fifth day after surgery

General information

rats were divided into the following four groups: i) control ii) ovariectomized iii) non-ovariectomized + EMF exposure iv) ovaiectomized + EMF exposure

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
ばく露時間 continuous for 4 h/day during 6 months, starting on the fifth day after surgery
ばく露装置
ばく露の発生源/構造
ばく露装置の詳細 two pairs of Helmholtz coils with a diameter of 70 cm, each consisting of 125 turns of insulated copper wire with a diameter of 1.5 mm; coils placed vertically facing each other at a distance of 47 cm; methacrylate cages (43 cm x 42 cm x 15 cm) placed between the coils; rats could move freely inside the cage; exposure system placed inside a 130 cm x 65 cm x 80 cm Faraday cage
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 1.5 mT - 測定値 - -

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:
  • ばく露前
  • ばく露後

研究の主なアウトカム(著者による)

Although there was no significant difference in bone mineral density values among the groups before magnetic field exposure, the bone mineral density values increased significantly after six months in the groups 3 (non-ovariectomized, exposed) and 4 (ovariectomized, exposed) and were reduced in group 2 (ovariectomized only) compared to the control group. The concentrations of bone-specific alkaline phosphatase, osteocalcin, and osteoprotogerin in the three groups also changed in a significant way compared to the control group (increase in the exposed groups 3 and 4 indicating increased osteoblast growth and activity and decrease in group 2). The N-telopeptide level decreased in the exposed groups 3 and 4 (indicating a decrease in osteoclast activity) and increased in group 2 compared with the control group.
The data suggest that osteoporosis can be inhibited by extremely low frequency magnetic fields treatments. Extremely low frequency magnetic fields may be useful in the prevention of osteoporosis in ovariectomized rats.

研究の種別:

研究助成

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