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

[1950 MHz TD-SCDMA電磁界へのばく露はカスパーゼ-3依存性経路を介して星状膠細胞のアポトーシスに影響する] med./bio.

Exposure to 1950-MHz TD-SCDMA Electromagnetic Fields Affects the Apoptosis of Astrocytes via Caspase-3-Dependent Pathway.

掲載誌: PLoS One 2012; 7 (8): e42332

この論文は、SDラットから取り出した星状膠細胞およびC6神経膠腫細胞に、搬送周波数1950-MHzのTD-SCDMA携帯電話電磁界ばく露SAR 5.36 W/kg;ばく露時間は12、24、48 時間)を与え、無ばく露群とばく露群での細胞変化を比較すると共に、無ばく露、12、24、48 時間ばく露後の2種類の細胞をそれぞれヌードマウス(雄のBALB/c免疫不全マウス;8群各3匹)に皮下注入移植して、28日後に発がん性試験を行った。その結果、48時間ばく露の星状膠細胞で、ミトコンドリア損傷アポトーシス誘導アポトーシスの特徴であるカスパーゼ-3増強、アポトーシス促進的タンパクbaxの発現レベル増加、アポトーシス阻害的なbcl-2発現レベル低下などが見られた(無、12,24時間ばく露群では有意差なし);C6神経膠腫細胞では全ての群に有意差はなかった;星状膠細胞移植した場合、全ての群で腫瘍発生はなかったが、C6神経膠腫細胞の場合は全ての群で腫瘍発生が起こり、無ばく露群およびばく露群で腫瘍の大きさや生物学的特徴に有意差はなかった、などの所見を報告している。

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研究目的(著者による)

To investigate whether a radiofrequency field exposure alters the biology of glial cells and acts as a tumor-promoting agent.

詳細情報

Normal rat astrocytes and C6 glioma cells were exposed to a 1959 MHz TD-SCDMA (Time Division Synchronous Code Division Multiple Access) signal. Different endpoints were regarded: 1.) apoptosis, 2.) cell proliferation, 3.) morphological changes and ultrastructure, 4.) expression of the genes bax and bcl-2, 5.) expression of the protein caspase-3 and 6.) tumorigenicity assay in nude mice was conducted. Therefore, astrocytes and C6 cells, previously exposed, were injected into mice (n=3 per group). Mice were sacrificed 28 days later and examined.
In each experiment cells were divided into four groups: unexposed and exposed for 12, 24 or 48 hours.

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 12, 24, 48 h
  • 電力: 251.19 mW (24 dBm - nominal maximum power of TD-SCDMA mobile phones)
  • SAR: 5.36 W/kg (according to the antenna calibration certificate)

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 12, 24, 48 h
Additional information TD-SCDMA (Time Division Synchronous Code Division Multiple Access)
ばく露装置
ばく露の発生源/構造
ばく露装置の詳細 dipole antenna fixed under the cell plates; four bottles with cells exposed simultaneously; cell plates kept at a constant temperature of 37°C
パラメータ
測定量 種別 Method Mass 備考
電力 251.19 mW - 測定値 - 24 dBm - nominal maximum power of TD-SCDMA mobile phones
SAR 5.36 W/kg - - - according to the antenna calibration certificate

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:
  • ばく露前
  • ばく露後

研究の主なアウトカム(著者による)

Astrocytes: After 48 h exposure, the morphology and ultrastructure changed compared to the unexposed and 12 or 24 h exposed cells. Many cells became shorter and thicker and the mitochondria showed uneven distribution, irregular shapes, swelling, christa break and cavitation. Exposure for 48 h significantly inhibited the cell growth compared to the unexposed group. The percentage of apoptotic cells after 48 h of exposure was more than three times higher than that of other groups. A significant down-regulation of bcl-2 mRNA levels and up-regulation of bax mRNA levels was detected after 48 h of exposure in comparison to the unexposed group, while the gene expression was not influenced in 12 and 24 h exposed cells. A significant increase of the caspase-3 protein was detected after 48 h exposure, but not in the other groups. Tumor formation was not detected.
C6 cells: No differences occurred between unexposed, 12, 24 and 48 h exposed groups in all experiments.
The authors summarize that 48 h of exposure to a TD-SCDMA signal showed no evident effects on glial tumor formation, but damaged the mitochondria of astrocytes and induced apoptosis via a caspase-3-dependent pathway involving bax and bcl-2.

研究の種別:

研究助成

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