Lack of promoting effect of titanium dioxide particles on chemically-induced skin carcinogenesis in rats and mice

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著者

    • Sagawa Yoko SAGAWA Yoko
    • Department of Geriatric and Environmental Dermatology, Nagoya City University Graduate School of Medical Sciences
    • FUKAMACHI Katsumi
    • Department of Molecular Toxicology, Nagoya City University Graduate School of Medical Sciences
    • SAKAI Yuto
    • Department of Molecular Toxicology, Nagoya City University Graduate School of Medical Sciences
    • SUZUI Masumi
    • Department of Molecular Toxicology, Nagoya City University Graduate School of Medical Sciences
    • TSUDA Hiroyuki
    • Nanotoxicology Project Laboratory, Nogoya City University, Nagoya City University Graduate School of Pharmaceutical Sciences
    • MORITA Akimichi
    • Department of Geriatric and Environmental Dermatology, Nagoya City University Graduate School of Medical Sciences

抄録

Nano-sized titanium dioxide particles (TiO<sub>2</sub>) are widely used in cosmetics, sunscreens and food additives. We previously reported that topical application of non-coated rutile type TiO<sub>2</sub> did not exhibit a promoting effect on ultraviolet B-initiated skin carcinogenesis in rats, and that this was likely due to lack of penetration of TiO<sub>2</sub> into the epidermis. In the present study, we examined the promoting effect of silicone coated TiO<sub>2 </sub>(sTiO<sub>2</sub>) suspended in silicone oil and non-coated TiO<sub>2 </sub>(ncTiO<sub>2</sub>) suspended in Pentalan 408<sub> </sub>on a two-stage skin chemical carcinogenesis model: sTiO<sub>2</sub> suspended in silicon oil forms smaller particles than ncTiO<sub>2</sub> suspended in Pentalan because of the smaller sizes of aggregates formed. The model used skin carcinogenesis-sensitive human c-Ha-ras proto-oncogene transgenic mice (rasH2) and rats (Hras128) and their wild-type counterparts and CD-1 mice to test the effects of topical application of TiO<sub>2</sub>. Animals were initially treated with a single dose of 7,12-dimethylbenz[a]anthracene (DMBA) and then with 0, 10, or 20 mg sTiO<sub>2</sub> (mice) or 0, 50, or 100 mg ncTiO<sub>2</sub> (rats). The incidence and multiplicity of skin tumors (squamous cell papilloma and carcinoma) did not increase over DMBA alone controls in skin carcinogenesis-sensitive mice or rats or wild-type animals. Analysis of rat skin indicated that sTiO<sub>2</sub> and ncTiO<sub>2</sub> did not penetrate though either healthy or damaged skin. Furthermore sTiO<sub>2</sub> did not penetrate an <i>in vitro</i> human epidermis model. Our results indicate that treatment with sTiO<sub>2</sub> or ncTiO<sub>2</sub> did not promote skin carcinogenesis in mice or rats, probably due to lack of penetration through the epidermis.

収録刊行物

  • Journal of toxicological sciences

    Journal of toxicological sciences 37(2), 317-327, 2012-04-01

    一般社団法人 日本毒性学会

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各種コード

  • NII論文ID(NAID)
    10030126738
  • NII書誌ID(NCID)
    AN00002808
  • 本文言語コード
    ENG
  • 資料種別
    ART
  • ISSN
    03881350
  • NDL 記事登録ID
    023674451
  • NDL 請求記号
    Z19-1022
  • データ提供元
    CJP書誌  NDL  J-STAGE 
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