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

[マウス幹細胞での遺伝子発現に対するテラヘルツ放射の非熱的影響] med./bio.

Non-thermal effects of terahertz radiation on gene expression in mouse stem cells.

掲載誌: Biomed Opt Express 2011; 2 (9): 2679-2689

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研究目的(著者による)

Mesenchymal mouse stem cells were exposed to Terahertz waves to study whether mammalian cells exhibit specific cellular and/or molecular effects, unrelated to the temperature changes. To examine the eventual thermal effect locally, i.e. in the cells, the Terahertz-induced transcriptional activation of hyperthermic genes was quantified, and their expression levels were compared with previously reported differentially expressed genes (Bock et al. 2010).

詳細情報

The irradiations were performed at biologically-low temperatures (26-27°C), and at low Terahertz power densities (1-3 mW/cm²), in order to minimize thermal effects on the gene activity. To analyze the possible changes in the temperature, simulations and experimental measurements were applied.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 10 THz
Modulation type: pulsed
ばく露時間: continuous for 2 h or 9 h
ばく露2: 2.52 THz
Modulation type: CW
ばく露時間: continuous for 2 h

ばく露1

主たる特性
周波数 10 THz
タイプ
  • electromagnetic field
ばく露時間 continuous for 2 h or 9 h
Additional information broad band (1-30 THz) radiation centered at 10 THz
Modulation
Modulation type pulsed
Pulse width 0.035 ps
Repetition frequency 1 kHz
ばく露装置
ばく露の発生源/構造
  • two-color laser photoionization gas plasma mixing
ばく露装置の詳細 laser beam directed by a 90° off-axis parabolic gold mirror onto the bottom of the 4 cm diameter parafilm-sealed tissue culture dish
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電力密度 1.2 mW/cm² - 測定値 - at the center of the beam through empty plate
電力密度 0.25 mW/cm² - 測定値 - near the edge of the empty culture plate
電力密度 1 mW/cm² mean 推定値 - -

ばく露2

主たる特性
周波数 2.52 THz
タイプ
  • electromagnetic field
ばく露時間 continuous for 2 h
Modulation
Modulation type CW
ばく露装置
ばく露の発生源/構造
  • optically pumped molecular gas laser
ばく露装置の詳細 laser beam directed by a 90° off-axis parabolic gold mirror onto the bottom of the 4 cm diameter parafilm-sealed tissue culture dish
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電力密度 3 mW/cm² - 測定値 - at the center of the beam

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)

No cell death was visually observed. No effects on the cell membranes were visually discernable. No lipid inclusions were found in the control samples or in the samples that were exposed to 2 hours of CW irradiation (exposure 2). However, lipid droplet-like inclusions were observed in the cellular cytoplasm after 2 and 9 hours of broad-band exposure (exposure 1) and the morphological changes seemed to be dependent of the exposure duration (fewer inclusions after 2 h than after 9 h) and frequency.
Temperature increases were minimal, and the expression of the investigated heat shock proteins (hsp105, hsp90 and CPR) was unaffected, while the gene expression of the other genes (adiponectin, GLUT4, and PPARG) showed clear effects of the Terahertz irradiation after prolonged, broad-band exposure (as revealed in Bock et al. 2010). These effects where observed under irradiation conditions that caused minimal temperature changes, and in the explicit absence of any discernable response of heat shock and cellular stress genes.

研究の種別:

研究助成

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