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

[足場材を用いない三次元細胞培養システムの電磁界ばく露] med./bio.

Electromagnetic exposure of scaffold-free three-dimensional cell culture systems.

掲載誌: Bioelectromagnetics 2011; 32 (5): 351-359

【背景】近年の、電磁界ばく露非熱的生物学的影響の可能性に関する多数のインビトロ研究は、代表的には初代細胞または細胞株単一層を対象として行われている。しかしながら、インビボ細胞は3次元構造であるため、2次元の細胞層系は生理学的妥当性を欠く。単一層での研究では、細胞細胞間及び細胞細胞基質間の相互作用が生きている組織とは異なるため、実験結果を物差しにしてインビボ系について判断することには慎重さが望まれる。【目的】上述の問題を克服するために、我々は細胞足場材なしの3次元細胞培養系を用い、900MHzの電磁界による電気生理学的影響の探索を行うこと。【方法】一定の回転で解離心筋細胞を球形に再凝集させ、微小電極アレイを用いて、この細胞スフェロイド(多細胞球体)の(活動電位の)無侵襲細胞外記録を行った。ストリップライン型ばく露装置を用い、この3次元細胞培養系をパルス電磁界ばく露させた。【結論】ばく露パラメータを慎重に選択すれば、微小電極アレイチップの電極および導線による電磁界の不均一性が細胞スフェロイド内の電磁界分布に与える影響は小さくできることが見出された。

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研究目的(著者による)

To study the effects of electromagnetic field exposure on a scaffold-free (i.e. without synthetic polymers or biomaterials) three-dimensional (3D) cell culture system.

詳細情報

The study aimed to achieve an improved physiological relevance by a 3D in vitro model. Several studies have already revealed distinct differences between monolayer and 3D cell cultures in terms of cellular behavior. By using rotation-mediated scaffold-free spheroids histotypic self-organization is enabled.
In the first part of experiments, cardiac myocyte spheroids were exposed to pulsed electromagnetic fields (field 2). In a second part the pulse frequency of the electromagnetic field was adjusted to the beat rate of a single spheroid (field 3). By varying the pulse frequency in the range of 5-20%, possible direct interferences of electromagnetic field frequencies with the beat rate were explored. In positive controls the beat rate of spheroids was investigated as a function of temperature (field 1).

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: CW
ばく露時間: continuous for 1 min
positive control
  • SAR: 1 W/kg (within the spheroids)
ばく露2: 900 MHz
Modulation type: pulsed
ばく露時間: continuous for 1 min
  • SAR: 100 mW/kg (within the spheroids)
  • SAR: 250 mW/kg (within the spheroids)
ばく露3: 900 MHz
Modulation type: pulsed
ばく露時間: continuous for 1 min
  • SAR: 100 mW/kg (within the spheroids)

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 1 min
Additional information positive control
Modulation
Modulation type CW
ばく露装置
ばく露の発生源/構造
ばく露装置の詳細 TEM cell constructed as a 1000 mm long stripline consisting of a 1 mm tin-plated steel sheet and a septum at a distance of 50 mm; stripline equipped with a temperature controller; temperature controller switched off
パラメータ
測定量 種別 Method Mass 備考
SAR 1 W/kg - 計算値 - within the spheroids

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 1 min
Modulation
Modulation type pulsed
Duty cycle 50 %
Repetition frequency 8.3 Hz
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
ばく露装置の詳細 temperature controller switched on
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
SAR 100 mW/kg - 計算値 - within the spheroids
SAR 250 mW/kg - 計算値 - within the spheroids

ばく露3

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 1 min
Modulation
Modulation type pulsed
Repetition frequency 1 Hz
Additional information

pulse frequency adjusted to the beat rate

ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
ばく露装置の詳細 temperature controller switched on
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
SAR 100 mW/kg - 計算値 - within the spheroids

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
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

None of the analyzed electrophysiological parameters were significantly changed under exposure. Thus, the data showed no influence of the electromagnetic field on cardiac contractions.
However, the data showed that spheroids under the present conditions are excellent candidates for electromagnetic field exposure experiments. Electromagnetic field disturbances due to the recording electrodes were only minor. Compared to monolayer cultures, spheroids are contractile for a longer period of time and thus are a promising cell culture system for long-term exposure studies.

研究の種別:

研究助成

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