Protective effects of melatonin against low- and high-LET irradiation

Guangming Zhou, Tetsuya Kawata, Yoshiya Furusawa, Mizuho Aoki, Ryoichi Hirayama, Koichi Ando, Hisao Ito

研究成果: Article査読

27 被引用数 (Scopus)

抄録

To investigate the protective effects of melatonin against high-LET ionizing radiation, V79 Chinese hamster cells were irradiated with 100 keV/μm carbon beam. Parallel experiments were performed with 200 kV X-rays. To avoid the impact from extra solvents, melatonin was dissolved directly in culture medium. Cells were cultured in melatonin medium for 1 hr before irradiation. Cell inactivation was measured with conventional colony forming assay, medium containing 6-thioguanine was used for the selection of mutants at hprt locus, and the cell cycle was monitored by flow cytometry. Both carbon beam and X-rays induced cell inactivation, hprt gene mutation and cell cycle G2 block dose-dependently. But carbon beam showed stronger effects as indicated by all three endpoints and the relative biological effectiveness (RBE) was 3.5 for cell killing (at 10% survival level) and 2.9 for mutation induction (at 5 × 10-5 mutants/cell level). Melatonin showed protective effects against ionizing radiation in a dose-dependent manner. In terms of cell killing, melatonin only increased the survival level of those samples exposed to 8Gy or larger of X-rays or 6 Gy or larger of carbon beam. In the induction of hprt mutation and G2 block, melatonin reduced such effects induced by carbon beam but not by X-rays. The results suggest that melatonin reduces the direct interaction of particles with cells rather than an indirect interaction. Further studies are required to disclose the underlying mechanisms.

本文言語English
ページ(範囲)175-181
ページ数7
ジャーナルJournal of radiation research
47
2
DOI
出版ステータスPublished - 2006

ASJC Scopus subject areas

  • 放射線
  • 放射線学、核医学およびイメージング
  • 健康、毒物学および変異誘発

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