この研究は、携帯電話の連続波（CW）の915MHzマイクロ波の非熱効果を、妊娠ラットを用いて調べた。非熱効果を評価するために、マイクロ波および熱による効果を比較した。36匹の妊娠ラットを6群に割り当てた：入射電力密度0.6または3 mW / cm2の915 MHzマイクロ波の90分間ばく露群、この２つの入射電力密度のばく露により生じる結腸温上昇1.0または3.5℃に対応する上昇を生じさせるための、38または40 ℃の温水浴群、熱中性と見なされる34 ℃の温水浴群,および対照群である。その結果、子宮胎盤循環および胎盤内分泌および免疫機能における有意な差異が、34 ℃と38℃の温水浴群の間で見られたが、34 ℃の温水浴群と0.6mW / cm2ばく露群の間では見られなかった；対照的に、3 mW / cm2ばく露群での子宮胎盤血流およびエストラジオールの減少は、40 ℃の温水浴群に比べ有意であった；これらの知見は、0.6 mW / cm2の915MHz（これは0.4W / kgのSARに相当し、米国規格協会（ANSI）の最大許容ばく露レベルに一致する）が、血中のエストラジオールおよびプロゲステロン、脾臓のナチュラルキラー細胞活性、および子宮胎盤循環に非熱的影響を及ぼさないことを示唆する、と報告している。
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To investigate the effects in pregnant rats exposed to non-thermal 915 MHz microwaves.
In six different treatment groups a total of 36 rats were examined: 1.) rats exposed to microwaves at 0.6 mW/cm2, 2.) rats exposed to microwaves at 3 mW/cm2, 3.) rats immersed in water at 38°C (induced the same colonic temperature increase as the group exposed to 0.6 mW/cm2 microwaves), 4.) rats immersed in water at 40°C (induced the same colonic temperature increase as the group exposed to 3 mW/cm2 microwaves), 5.) rats immersed in 34°C water (considered to be thermo-neutral), 6.) control rats.
|ばく露時間||continuous for 90 min|
|Additional information||Padilla JM, Bixby RR. Using Dewar flask calorimetry and rectal temperatures to determine the SARs of small rodents. USAFSAM-TP-86-3. TX, USA: Brooks AFB 1986.|
|チャンバの詳細||The environment of the exposure facility was maintained at 21-23 °C and 50-60% humidity.|
|ばく露装置の詳細||Rats were placed individually into semi-cylindrical acrylic plastic holders (inner diameter 60 mm, length 170 mm, walls 5 mm) and exposed in the device described previously [Inaba et al., 1992]. Two holders were put into the applicator with their long axis oriented parallel to the electric field.|
|Additional information||Rats were assigned to six groups: exposed to EMF at 0.6 or 3 mW/cm²; immersed in water at 38, 40 °C (inducing about the same increase in colonic temperature as the EMF) or at 34 °C (thermoneutral) or in a control group.|
Significant differences in the utero-placental circulation and in the placental endocrine functions between pregnant rats immersed in water at 34 and 38°C were identified, but not between rats immersed at 38°C and those exposed to microwaves at 0.6 mW/cm2. By contrast, significant decreases in the utero-placental blood flow and estradiol level in rats exposed to microwaves at 3 mW/cm2 as compared with those immersed in water at 40°C were observed. Therefore, microwaves at exposure levels that increase core temperature by about 3.5°C seem likely to produce utero-placental dysfunctions through thermal and nonthermal actions.
The microwave exposure to 0.6 mW/cm2 and water immersion at 38°C reduced splenic natural killer cell activity, but microwaves at 3 mW/cm2 did not change splenic natural killer cell activity as compared to the group exposed to 34°C water immersion.
In conclusion, the exposure to microwaves at 0.6 mW/cm2 (maximum permissible exposure level recommended by ANSI) do not exert nonthermal effects on the utero-placental blood flow, blood estriol and progesterone level, and splenic natural killer cell activity.