研究のタイプ: 治療に関する研究 (experimental study)

[短報:肝がん移植マウスに対するX線と組み合わせた100 Hz磁界の影響] med./bio.

The effect of 100 Hz magnetic field combined with X-ray on hepatoma-implanted mice

掲載誌: Bioelectromagnetics 2011; 32 (4): 322-324

【背景】先の細胞実験にて、100Hz磁界がX線誘発された肝がん細胞BEL-7402におけるアポトーシス増強に影響を与えることを示した。目的 :肝がん移植されたBalb/cマウスの治療における100Hz磁界とX線の相乗効果についてさらに探求すること。【方法】平均磁束密度0.7 mT の100 Hz 磁界ばく露ソレノイドコイルにより、6 MVのX線照射はリニア加速器により行われた。肝細胞がん細胞H22を移植されたマウスにおける腫瘍増殖および生存について腫瘍直径と生存日数による評価を行った。100 Hz 磁界擬似ばく露ばく露:回数は5回一定)、X線照射擬似ばく露、4 Gy照射、8 Gy照射)を組み合わせた6つのばく露条件群について実験した。また、4 Gy X線照射と組み合わせる磁界ばく露の回数(5回全てが擬似ばく露ばく露3回、ばく露5回)を変えて、腫瘍増殖と生存日数への影響を調べる実験も行った。各群のデータの比較には対数順位検定およびスチューデントt検定を用いた。【結果】磁界ばく露5回と4 Gy X線照射との組み合わせにおいて、磁界またはX線の単独ばく露に比較して有意な生存日数の延長と腫瘍サイズの減少が見られた。また4 Gy X線照射と組み合わせた磁界ばく露の回数が多いほど生存日数は改善され、腫瘍増殖抑制された。【結論】肝がん移植マウスにおける生存日数の改善と腫瘍増殖抑制について、100Hz磁界は4 Gy X線との相乗作用をもつ可能性が示唆された。

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研究目的(著者による)

To study the possible synergism between 100 Hz magnetic field exposure and X-rays in terms of their influence on tumor growth inhibition and survival time in tumor-bearing mice.

詳細情報

Implanted tumors were allowed to grow for 7-14 days until the tumor diameter reached the size of 2 cm before treatment was started.
Mice were divided into six groups (n = 10): 1) sham X-ray and five periods of sham exposure to magnetic field (each period = 60 min with an interval of 12 h); 2) sham X-ray and five periods of 100 Hz magnetic field exposure; 3) 4 Gy X-ray followed (within half an hour) by five periods of sham exposure to magnetic fields; 4) 8 Gy X-ray followed by five periods of sham exposure; 5) 4 Gy X-rays followed by five periods of magnetic field exposure; and 6) 8 Gy X-ray followed by five periods of magnetic field exposure.
Additionally, to study whether more magnetic field exposure periods could have a greater synergistic effect with X-rays than fewer periods, three groups of tumor-bearing mice were examined (n = 20): 1) 4 Gy X-rays followed by five periods of sham exposure; 2) 4 Gy X-ray followed by three periods magnetic field exposure and two periods of sham exposure; and 3) 4 Gy X-rays followed by five periods of magnetic field exposure.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 100 Hz
ばく露時間: 3 or 5 times 60 min with a 12 h interval between them

ばく露1

主たる特性
周波数 100 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 3 or 5 times 60 min with a 12 h interval between them
Additional information animals were treated in different groups: i) sham X-ray exposure + 5 times sham EMF exposure ii) sham X-ray exposure + 5 times EMF exposure iii) 4 Gy X-ray exposure + 5 times sham EMF exposure iv) 8 Gy X-ray exposure + 5 times sham EMF exposure v) 4 Gy X-ray exposure + 5 times EMF exposure vi) 8 Gy X-ray exposure + 5 times EMF exposure vii) 4 Gy X-ray exposure + 3 times EMF exposure + 2 times sham EMF exposure
ばく露装置
ばく露の発生源/構造
ばく露装置の詳細 15 cm x 20 cm solenoid with 270 turns of 2 mm diameter copper wire wound in three layers; mouse anesthetized and placed inside the solenoid
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 0.7 mT mean 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:
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 five periods of combined 100 Hz magnetic field exposure and 4 Gy X-ray could significantly extend the overall days of survival and reduce the tumor size compared to magnetic field exposure or X-ray alone. Furthermore, a greater number of magnetic field exposure periods (5 compared to 3) could further improve the survival and inhibit tumor growth in hepatoma-implanted mice when combined with 4 Gy X-ray.
In conclusion, these findings suggest that 100 Hz magnetic fields could possibly synergize with 4 Gy X-ray in terms of survival improvement and tumor inhibition in hepatoma-implanted mice.

研究の種別:

研究助成

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