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

[無線周波電磁界にばく露されたヒト血液リンパ球における適応応答の誘導:ユニバーサルモバイル通信システム(UMTS)信号と比吸収率の影響] med./bio.

Induction of an adaptive response in human blood lymphocytes exposed to radiofrequency fields: Influence of the universal mobile telecommunication system (UMTS) signal and the specific absorption rate.

掲載誌: Mutat Res Genet Toxicol Environ Mutagen 2012; 747 (1): 29-35

この実験研究はヒト末梢血リンパ球において、無線周波電磁界RFばく露により適応応答(AR)[訳者注]が生じるか否かを調べた。9人の健常被験者から採取したリンパ球細胞をphytohaemagglutinin (PHA)添加培養液で培養した後、ADとして、異なるSAR(1.25、0.6、0.3、0.15 W/kg)のUMTS信号(1950 MHzばく露または擬似ばく露を与え、その後、CDとして100 ng/ml のマイトマイシンMMC)を与えて、回収したリンパ球における小核MN)の頻度を遺伝毒性の指標として測定した。その結果、SAR 0.3 W/kg のRFを事前にADとした与えた場合、AD無しの場合に比べてMN頻度が有意に減少したことから、RFばく露によるARが見られたと報告している。[訳者注]適応応答とは、前もって適応dose(AD)を与えると、その後に与えるチャレンジdose(CD)に対する応答が弱くなる現象。この研究では、基礎実験として、実験に使用した9検体にMMCによるARがあるか否かを、ADとして1 ng/ml のMMCを与え、CDとして100 ng/m のMMCを与えた場合の反応をAD無しの場合と比較して調べた。その一方で、ADとしてRFばく露を与えた場合について、AD無し(擬似ばく露)の場合と比較することが本研究の主目的である。

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研究目的(著者による)

To examine the influence of different specific absorption rates on the adaptive response induced by the exposure of human blood lymphocytes to radiofrequency fields.

詳細情報

Former studies have shown that different cell types exposed to an extremely small adaptation dose of a genotoxic agent are less susceptible to the induction of a genetic damage when given a higher challenge dose of the same or a similar genotoxic agent. The induction of an adaptive response was shown to be influenced by several factors (e.g. the dose used for adaptation, the dose rate, the time between the adaptation and challenge doses).
Blood lymphocytes of nine male healthy donors were stimulated for 24 h with phytohaemagglutinin and then exposed for 20 hours to an adaptive dose of 1950 MHz radiofrequency field at different specific absorption rates (1.25, 0.6,0.3 and 0.15 W/kg). This was followed by a challenge dose of 100 ng/ml mitomycin C. Cells were collected after 72 h total culture period and the frequency of micronuclei was recorded.
The lymphocytes from donors 1-3 were exposed at 1.25 and 0.3 W/kg while the lymphocytes from donors 4-6 were exposed at 0.6 and 0.15 W/kg. Whole blood samples from donors 7-9 were employed to set up cultures exposed at 1.25 and 0.3 W/kg on day 1, and at 0.6 and 0.15 W/kg on day 2.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 1,950 MHz
ばく露時間: continuous for 20 h
  • SAR: 0.3 W/kg (in the outer dishes in experiment 1)
  • SAR: 1.25 W/kg (in the inner dishes in experiment 1)
  • SAR: 0.15 W/kg (in the outer dishes in experiment 2)
  • SAR: 0.6 W/kg (in the inner dishes in experiment 2)

General information

Cells were treated in the following four groups: i) RF exposure ii) sham exposure iii) RF exposure + 100 ng/ml mitomycin C (MMC) iv) sham exposure + 100 ng/ml MMC experiment 1: lymphocytes from donors 1-3 were exposed at 1.25 and 0.3 W/kg experiment 2: lymphocytes from donors 4-6 were exposed at 0.6 and 0.15 W/kg experiment 3: blood samples from donors 7-9 were employed to set up cultures exposed at 1.25 and 0.3 W/kg on day 1, and at 0.6 and 0.15 W/kg on day 2

ばく露1

主たる特性
周波数 1,950 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 20 h
ばく露装置
ばく露の発生源/構造
チャンバの詳細 109.2 mm high and 54.6 mm wide WR430 rectangular short-circuited waveguide with a coaxial adapter at the feeding side
ばく露装置の詳細 both waveguides (for exposure and sham exposure) placed in the same incubator; in each waveguide four 35 mm Petri dishes were positioned one above the other with a 22 cm distance between the two middle dishes and a 26 distance between the middle and the outer dishes; when the centres of the samples were at a distance of 0.56 λ from the short circuit the efficiency of the exposure system was approximately 70% and the degree of non-uniformity in SAR was 0.33 in all samples.
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
SAR 0.3 W/kg - 計算値 - in the outer dishes in experiment 1
SAR 1.25 W/kg - 計算値 - in the inner dishes in experiment 1
SAR 0.15 W/kg - 計算値 - in the outer dishes in experiment 2
SAR 0.6 W/kg - 計算値 - in the inner dishes in experiment 2

Reference articles

  • Brescia F et al. (2009): [Jurkat細胞における活性酸素種の形成はUMTS1950 MHz放射ばく露によって、あるいは鉄イオンとの複合ばく露によって強化されない]
  • Sannino A et al. (2006): [1950 MHz変調信号ばく露後のヒト末梢血リンパ球における細胞毒性と遺伝子毒性の影響評価]

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:

研究の主なアウトカム(著者による)

In cell cultures of all nine donors, the frequencies of micronuclei in the lymphocytes exposed or sham exposed alone were not significantly different from those in untreated controls, while treatment of the cells with mitomycin C alone resulted in a significant increase compared with the untreated controls.
The results were different in different donors. According to the results between "radiofrequency field + mitomycin treatment" and the corresponding "sham exposure + mitomycin treatment", there were significant differences (decreases) at both 0.3 W/kg and 0.6 W/kg specific absorption rates. The data indicated that a radiofrequency field at 0.3 W/kg was a more reliable specific absorption rate to induce an adaptive response than a radiofrequency field at 0.6 W/kg.
Two donors did not show an adaptive response to mitomycin C nor to the radiofrequency field exposure.
The proliferation index in all cell cultures was not significantly different between untreated control lymphocytes, those exposed to "radiofrequency + mitomycin C", and those treated with mitomycin C alone.

研究の種別:

研究助成

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