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

[メラトニンはマイクロ波ばく露で引き起こされる酸化的ストレスからラットの胸腺を保護し胸腺細胞の増殖／アポトーシスを変化させる] med./bio.

Melatonin protects rat thymus against oxidative stress caused by exposure to microwaves and modulates proliferation/apoptosis of thymocytes

著者: Sokolovic D, Djordjevic B, Kocic G, Veljkovic A, Marinkovic M, Basic J, Jevtovic-Stoimenov T, Stanojkovic Z, Sokolovic DM, Pavlovic V, Djindjic B, Krstic D
掲載誌: Gen Physiol Biophys 2013; 32 (1): 79-90
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この研究は、ラットを用いた実験で、マイクロ波ばく露がラットの胸腺組織に与える影響（酸化ストレス、DNA断片化、アポトーシス、および増殖）を調べ、さらに、それらの影響を対するメラトニンの効果を評価した。ウィスターラットを4群（各n = 21）に分けた。すなわち、擬似ばく露+生理食塩水投与群、擬似ばく露+メラトニン投与群、マイクロ波ばく露群、マイクロ波ばく露+メラトニン投与群である。携帯電話を用いたマイクロ波ばく露を、1日4時間で、20、40および60日間継続した。メラトニン（2 mg / kg）または生食の腹腔内投与も毎日行った。ばく露開始から20、40および60日目に、各群から7匹ずつ取り出して屠殺し、胸腺を摘出した。その結果、マイクロ波ばく露群において、マロンジアルデヒドおよびカルボニル基含有量の有意な増加、ならびにカタラーゼの減少およびキサンチンオキシダーゼ活性の増加が見られた；メラトニンは、マロンジアルデヒドおよびカルボニル基の含有量の増加を防止し、カタラーゼとキサンチンオキシダーゼ活性への影響を逆転させた；マイクロ波ばく露群では、アルカリ性および酸性の両方のDNase活性の増加、アポトーシス率の増加および胸腺細胞の増殖能低下が見られた；しかし、メラトニンは、アルカリ性および酸性のDNase活性の低下、アポトーシス率の低下、胸腺細胞の増殖率の上昇を引き起こした、と報告している。

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研究目的（著者による）

To examine the effect of a melatonin administration on oxidative stress parameters, DNA fragmentation, apoptosis and proliferation of thymocytes in microwave-exposed rats.

詳細情報

4 groups of rats were examined: 1.) sham exposure, treated with saline injection, 2.) sham exposure, injection of 2 mg melatonin per kg body weight, 3.) exposure and 4.) exposure, injection of 2 mg melatonin per kg body weight (21 rats per group). After 20, 40 and 60 days, seven animals of each group were anesthetized and killed after removing the thymus.

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 4 hours/day on 20, 40 or 60 consecutive days

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
特性
  • near field
ばく露時間 continuous for 4 hours/day on 20, 40 or 60 consecutive days
ばく露装置
ばく露の発生源／構造
  • セルラ－電話
  • Nokia 3110
ばく露装置の詳細 mobile phone was placed in a small perforated polycarbonated box in the center of the cage; seven freely moving rats per cage were placed on absorbing material made of rubber with wooden isolation surface
Sham exposure A sham exposure was conducted.
Additional information exposure was performed in the same room where all animals were housed or in another room (remark EMF-Portal: contradictory statements)
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 4.68 µT minimum 推定値 - -
磁束密度 8.69 µT maximum 推定値 - -
電界強度 9.88 V/m minimum 推定値 - -
電界強度 18.356 V/m maximum 推定値 - -
SAR 0.043 W/g minimum 推定値 - -
SAR 0.135 W/g maximum 推定値 - -

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）

In the exposed groups without melatonin (after 20, 40 and 60 days), the level of lipid peroxidation and protein oxidation, as well as the enzyme activities of catalase, xanthine oxidase, DNAse I and DNAse II were significantly increased compared to the control group. An administration of melatonin prevented these effects in the exposed group (except for the protein oxidation after 20 and 40 days).
The number of apoptotic cells was significantly increased in the exposed groups without melatonin compared to the control group. Moreover, the number of apoptotic cells increased with longer exposure duration. An administration of melatonin significantly reduced the apoptosis rate in the exposed group. The proliferation of the thymocytes was significantly decreased in the exposed groups without melatonin in comparison to the control group. This effect was stronger the longer the rats had been exposed. An administration of melatonin significantly increased the proliferation rate in the exposed group when compared to the exposed group without melatonin injection.
The authors conclude that melatonin could have a protective effect against oxidative stress and could modulate processes of apoptosis and proliferation in thymus tissue of microwave-exposed rats.

研究の種別:

研究助成

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