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

[緑茶カテキンはマイクロ波による心臓組織の酸化的損傷からラットを保護する] med./bio.

Green tea catechins protect rats from microwave-induced oxidative damage to heart tissue

著者: Kim MJ, Rhee SJ
掲載誌: J Med Food 2004; 7 (3): 299-304
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この研究は、ラット実験で、マイクロ波ばく露により心臓組織に生じた酸化的損傷に対する緑茶カテキンの効果を調べた。マイクロ波ばく露（2.45 GHz、15分）を受けたラットは、カテキンフリー（MW-0C群）、0.25 %カテキン（MW-0.25C群）、0.5 %カテキン（MW-0.5C群）の3つの食餌のうちの1つを摂取した。マイクロ波照射の6日後にラットを屠殺して、心臓組織を検査した。その結果、MW-0C群のシトクロムp450（還元状態で一酸化炭素と結合して450nmに吸収極大を示す色素）は、対照群の値に比べ、85 %増加した；MW-0.25CおよびMW-0.5C群のシトクロムp450値は、MW-0C群の値に比べ、それぞれ11 %および14 %低かった；NADPH-シトクロムp450還元酵素活性は、MW-0C群では対照群の値に比べ、29 %増加したが、MW-0.25CおよびMW-0.5C群では有意に低かった；スーパーオキシドジスムターゼ活性は、MW-0C群では対照群の値に比べ、34 %低下したが、MW-0.25CおよびMW-0.5C群では19 %および25 %上昇した；グルタチオンペルオキシダーゼの活性は、MW-0C群では28 %低下したが、カテキン補充群ではほぼ正常に保たれた；MW-0C群のスーパーオキシドラジカル濃度は、対照群の値に比べ、35 %増加した；MW-0.25CおよびMW-0.5C群のスーパーオキシドラジカル濃度は、MW-0C群の値に比べ、それぞれ11 %および12 %低かった、など多くの知見を報告している。

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研究目的（著者による）

To study the effects of green tea catechins (antioxidants) on oxidative damage in the heart tissue of microwave exposed rats.

詳細情報

The exposed rats received one of three diets: 1) catechin-free, 2) 0.25% catechin, or 3) 0.5% catechin. Each group consisted of ten rats. Rats were sacrificed 6 days after microwave irradiation

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: CW
ばく露時間: continuous for 15 min.
  • 電力密度: 40 mW/cm² (at a distance of 35 cm)
  • SAR: 9.2 W/kg average over mass (whole body)

General information

Microwave exposed animals were divided into three groups: i) catechin-free diet ii) 0.25 % catechin dietary supplement iii) 0.5 % catechin dietary supplement

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 15 min.
Modulation
Modulation type CW
ばく露装置
ばく露の発生源／構造
  • modified household microwave oven
パラメータ
測定量 値 種別 Method Mass 備考
電力密度 40 mW/cm² - 測定値 - at a distance of 35 cm
SAR 9.2 W/kg average over mass 測定値 whole body -

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）

Cytochrome P450 levels in the catechin-free microwave exposed group were increased by 85% compared with the control group. However, they were 11% and 14% lower in the "microwave + 0.25 % catechin" and "microwave + 0.5 % catechin" groups than in the catechin-free group.
NADPH-cytochrome P450 reductase enzyme activity in the catechin free group was increased by 29%, compared to the control group, but it was significantly less in the "microwave + 0.25 % catechin" and "microwave + 0.5 % catechin" groups.
Superoxide dismutase activity in the catechin-free group was decreased by 34%, compared with the normal group, but in the "microwave + 0.25 % catechin" and "microwave + 0.5 % catechin" groups it was 19% and 25% higher compared to the catechin-free group. The enzyme activity of glutathione peroxidase in the catechin-free microwave exposed group was decreased by 28% but remained near normal value with catechin supplements.
Superoxide radical concentration in the catechin-free microwave exposed group was increased by 35% compared with the control group. However, superoxide radicals in the "microwave + 0.25 % catechin" and "microwave + 0.5 % catechin" groups were 11% and 12% lower, respectively, compared with the catechin-free group.
Microwave exposure significantly increased levels of thiobarbituric acid-reactive substances, carbonyl group values, and lipofuscin contents, but catechins partially overcame the effects of the microwave irradiation.
In conclusion, oxidative damage was induced by microwave exposure. However, green tea catechin supplementation significantly reduced oxidative damage by weakening the free radical generating system, and strengthening of the antioxidative system.

研究の種別:

研究助成

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