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

[GSMマイクロ波への耳のばく露の影響：インビボおよびインビトロの実験研究] med./bio.

Effects of exposure of the ear to GSM microwaves: in vivo and in vitro experimental studies

著者: Aran JM, Carrere N, Chalan Y, Dulou PE, Larrieu S, Letenneur L, Veyret B, Dulon D
掲載誌: Int J Audiol 2004; 43 (9): 545-554
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この研究は、モルモットの耳に対するGSM携帯電話マイクロ波の影響を調べるために、2つのインビボ実験と1つのインビトロ実験を行った。第1のインビボ実験は、左耳に対するGSMマイクロ波ばく露（SAR：1, 2、4W/kgで、1日1時間、週5日、2ヶ月間継続）の開始前、終了直後、終了から2ヶ月後に、両耳の歪成分耳音響方射（DPOAE）を測定した（3つのばく露群と擬似ばく露群はそれぞれ8匹）。第2のインビボ実験は、第1と同じプロトコルを用いてばく露群（SAR：4W/kg、16匹）と擬似ばく露群（8匹）の聴性脳幹反応（ABR）を測定した。その結果、ばく露耳と非ばく露耳との間、およびばく露群と擬似ばく露群との間において、DPOAE振幅、ABR閾値に差は無かった：第2実験の一部として調べた急性影響では、ばく露前とばく露終了1時間後のABR閾値に有意差がなかった、と報告している。インビトロ実験は、新生仔ラット（n=15）から1個体につき2個のコルチ器官(OC)を摘出し、それぞれ1個をばく露（SAR：1W/kgで、24-48時間ばく露）、もう1個を擬似ばく露した。培養2-3日後、すべてのOCを光学顕微鏡検査した結果、この成長段階では正常に見えた,と報告している。

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研究目的（著者による）

To study the effects of mobile phone (GSM) microwaves on the ears of guinea pigs in in vivo and in in vitro experiments.

詳細情報

Since the brain is also exposed to the microwaves, changes in auditory functions could be caused by action at the level of the inner ear and/or central auditory pathways. The experiments were aimed at monitoring separately peripheral (by DPOAE measurements) and central auditory functions (auditory brainstem responses) after microwave exposure of the animals.
In the in vivo experiment, groups of eight guinea pigs had their left ear exposed to GSM microwaves and distortion product otoacoustic emissions (DPOAEs) were measured and auditory brainstem response thresholds were monitored.
In vitro, the two organs of Corti of 15 newborn rats were isolated and placed in culture.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 900 MHz
Modulation type: pulsed
ばく露時間: repeated daily exposure, 1 h/day, 5 days/week, for 2 months
in vivo
  • SAR: 1 W/kg mean
  • SAR: 2 W/kg mean
  • SAR: 4 W/kg mean
ばく露2: 900 MHz
Modulation type: pulsed
ばく露時間: continuous for 24 h
in vitro
  • SAR: 1 W/kg unspecified

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 repeated daily exposure, 1 h/day, 5 days/week, for 2 months
Additional information in vivo
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Pulse type rectangular
Additional information

GSM modulation
ばく露装置
ばく露の発生源／構造
  • loop antenna, RF generator
チャンバの詳細 An eight-compartment setup was constructed from RF absorbing panels avoiding interference among antennas.
ばく露装置の詳細 Guinea pigs were held in a holding device composed of two sliding-yoke PVC tubes each with a V notch providing a hole for the neck in order to keep the head outside the tube and maintained straight by a sliding ring adjusted over the nose of the animal. The animal body could lie comfortably on a platform inside the tube assembly. The antenna was fixed horizontally at the level of the external auditory canal of the left ear in contact with the edge of the pinna.
Additional information Sham exposure took place under the same conditions but in the absence of RF field.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 1 W/kg mean 測定値 - -
SAR 2 W/kg mean 測定値 - -
SAR 4 W/kg mean 測定値 - -
測定および計算の詳細

Local SAR measurements were made on an anaesthetized guinea pig using a temperature probe inserted into the cochlea. The average of three measurements at 7, 17 and 34 W input to the loop antenna gave an SAR of 3.5 ± 0.4 W/kg per incident watt in the cochlea.

ばく露2

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 24 h
Additional information in vitro
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Pulse type rectangular
Additional information

GSM modulation
ばく露装置
ばく露の発生源／構造
  • wire-patch cell
チャンバの詳細 Two pieces of wire-patch cell (WPC) apparatus (see reference article) were used to expose the organs of Corti (OCs) in Petri dishes. Each WPC was placed in its own incubator for true blind operation.
ばく露装置の詳細 The WPC consisted of two parallel square metallic plates with the bottom one being powered with RF through a coaxial line passing through the top one. Four poles at the four corners between the plates allowed for optimal tuning of the device.
Additional information For each rat, one OC was exposed, and the other one was sham-exposed.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 1 W/kg unspecified 測定値 - -
測定および計算の詳細

Extensive dosimetric measurements showed that the uniformity of the SAR in the culture medium was very good (< 15%).

Reference articles

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:
  • 感覚器
  • ear
調査の時期:
  • ばく露前
  • ばく露後

研究の主なアウトカム（著者による）

The data showed no difference in DPOAE amplitudes or in auditory brainstem response thresholds between the exposed and non-exposed ears/groups.
Corti organs all appeared normal at this stage of development.
These data provided no evidence that microwave irradiation, at the levels produced by mobile phones, caused damage to the inner ear or the auditory pathways in the animals.

研究の種別:

研究助成

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