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

[45および41℃の熱ショック後のHSP27リン酸化は増加するが、非熱的なTDMAまたはGSMばく露後は見られない] med./bio.

HSP27 phosphorylation increases after 45°C or 41°C heat shocks but not after non-thermal TDMA or GSM exposures

著者: Vanderwaal RP, Cha B, Moros EG, Roti Roti JL
掲載誌: Int J Hyperthermia 2006; 22 (6): 507-519
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この研究は、ヒト子宮頸部がん由来のHeLa S3細胞株およびヒト臍静脈内皮細胞由来のEA.hy926細胞株を用いて、急性（45°Cで30分）または慢性（41°Cで2時間）の熱ショックへのばく露または無線周波電磁放射（RF）の非熱的ばく露が、HSP27リン酸化の変化を引き起こすか否かを調べた。無線周波電磁放射（RF）の非熱的ばく露には、847 MHz時分割多元接続（TDMA）電磁放射（SAR は5 W/ kg、ばく露時間は1、2または24時間）または900 MHz GSM変調電磁放射（SARは3.7 W/ kg、ばく露時間は1、2、または5時間）を用いた。HSP27リン酸化は、さまざまなリン酸化の形態を、それぞれの濃度測定による相対量を2次元ゲル電気泳動法により分析することにより評価した。また、リン酸化されたHSP27に特異的な抗体を用いて、HSP27リン酸化レベルの変化を検出した。すべての熱ショックおよびRFばく露条件について、対応するインキュベーターコントロールサンプルとともに同時分析した。各実験は3回繰り返した。その結果、熱ショックにより、HSP27のリン酸化の程度は熱量とともに変化した；急性の場合（45°C）、より高度にリン酸化した形態の割合が増加した；5 W/ kgのTDMAへの1、2、または24時間ばく露を受けたHeLa S3細胞では、対照群または擬似ばく露群と比較して、HSP27リン酸化のレベルに有意差はなかった；3.7 W/ kgの900 MHz GSMへの1、2、または5時間ばく露を受けたEA.hy926細胞では、擬似ばく露と比較してHSP27リン酸化のレベルに有意差はなかった、と報告している。

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研究目的（著者による）

To determine if in vitro exposure to hyperthermia or to non-thermal radiofrequency irradiation induces changes in the heat shock protein 27 (HSP27) phosphorylation of human cell lines.

詳細情報

Five different isoforms of the heat shock protein 27 (HSP27) were considered.
Each experiment was repeated three times.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 847 MHz
Modulation type: pulsed
ばく露時間: continuous for 1, 2 or 24 h
  • SAR: 5 W/kg mean
ばく露2: 900 MHz
Modulation type: pulsed
ばく露時間: continuous for 1, 2 or 5 h
  • SAR: 3.7 W/kg mean

ばく露1

主たる特性
周波数 847 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 1, 2 or 24 h
Modulation
Modulation type pulsed
Additional information

TDMA
ばく露装置
ばく露の発生源／構造
Distance between exposed object and exposure source 292 mm
チャンバの詳細 A detailed description of the radial transmission line used for exposure has been reported in several publications [Moros et al., 1998 and 1999]. The RTL was formed by two horizontal parallel conductive plates, 43 mm apart. The 6 mm thick bottom AL plate was highly thermally conductive thus minimising temperature gradients among flasks. A central conical AL antenna emitted TEM waves propagating radially outward and terminated by an annulus of RF-absorbing foam material braced by a thin lamina of perforated aluminium at 533 mm from the centre.
ばく露装置の詳細 A total of 16 T-75 culture flasks could be distributed angularly around the antenna with their centres located at a radius of 292 mm. The cell layer was between 247 and 338 mm from the centre. Each flask was dielectrically loaded with a 3 mm thick shim of alumina (Al2O3) in order to boost and homogenise the SAR distribution.
Sham exposure A sham exposure was conducted.
Additional information Cells in T-75 tissue culture flasks containing 40 ml of medium (height 5 mm) were exposed to RF radiation at 37°C or heat shock (2 h at 41°C or 30 min at 45°C). All heat shock and RF exposure conditions were analysed simultaneously along with a matched incubator control sample.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 5 W/kg mean 測定値 - -
Additional parameter details

"The above power settings were selected to produce a nominal time-averaged cell-layer SAR of 5.0 ± 2.1 W/kg for both signals." (?!)

測定および計算の詳細

This SAR value is based on a series of comprehensive measurements and includes variations due to the position of the flask but does not include potential measurement uncertainty usually estimated at ±10%. The degree of inhomogeneity (SD) is typical for this type of arrangement and has been validated by independent FDTD simulation studies [Pickard et al., 2000, publication 5405]. The larger than usual amount of medium was found to reduce the SAR non-uniformities.

ばく露2

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 1, 2 or 5 h
Modulation
Modulation type pulsed
Additional information

GSM
ばく露装置
ばく露の発生源／構造
  • E1と同じ装置
Sham exposure A sham exposure was conducted.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 3.7 W/kg mean 測定値 - -
Additional parameter details

"The above power settings were selected to produce a nominal time-averaged cell-layer SAR of 5.0 ± 2.1 W/kg for both signals." (?!)

Reference articles

  • Moros EG et al. (1999): [大量の培養瓶へのマイクロ波照射用広帯域遮蔽ばく露装置としての放射状送電線]
  • Moros EG et al. (1998): [小動物の長期間のUHF照射用のコンパクトなばく露装置：1電磁および環境面を考慮した設計]

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 exposure to hyperthermia (30 minutes at 45 °C acute, two hours at 45 °C chronic) significantly increased heat shock protein 27 (HSP27) phosphorylation.
No significant differences in the levels of heat shock protein 27 (HSP27) phosphorylation were observed in the exposure of HeLa S3 cells to TDMA.
The exposure of EA.hy926 cells to 900 MHz GSM did not induce significant differences in the levels of heat shock protein 27 (HSP27) phosphorylation.

研究の種別:

研究助成

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