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Subchronic exposure of titanium dioxide nanoparticles to hairless rat skin
Author(s) -
Adachi Koji,
Yamada Nanako,
Yoshida Yuichi,
Yamamoto Osamu
Publication year - 2013
Publication title -
experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 96
eISSN - 1600-0625
pISSN - 0906-6705
DOI - 10.1111/exd.12121
Subject(s) - hairless , stratum corneum , penetration (warfare) , chemistry , emulsion , nanoparticle , parakeratosis , epidermis (zoology) , transepidermal water loss , dermis , human skin , titanium dioxide , dermatology , biophysics , materials science , pathology , nanotechnology , medicine , anatomy , biochemistry , biology , genetics , operations research , engineering , metallurgy
The evaluation of the biological effects of industrial nanoparticles on the skin is necessary for their risk assessment. To clarify the influence of T i O 2 nanoparticles on the skin, we carried out a subchronic exposure study of T i O 2 nanoparticles to hairless rat skin. W / O emulsion containing 10 wt% T i O 2 nanoparticles and control emulsion was applied to the dorsal skin of H airless W istar Y agi rats once a day for a maximum period of 56 consecutive days. After 2, 4 and 8 weeks, skin samples were taken from the exposed skin area. Histopathologically, the particles were only located in the stratum corneum layer of epidermis and follicular epithelium. Focal parakeratosis and spongiosis were observed in the epidermis. Transmission electron microscopy with energy‐dispersive X ‐ray spectrometry ( EDX ) analysis failed to show T i O 2 nanoparticles in the viable skin areas. There was no evidence of T i O 2 penetration in the viable skin areas. In addition, titanium contents in several organs were determined using inductively coupled plasma mass spectroscopy. Increased titanium concentration was detected in lung samples of the T i O 2 emulsion‐treated groups after 8 weeks. It was most likely that the presence of T i O 2 in the lungs was not caused by direct absorption of nanoparticles from the skin but was due to rats inhaling the nanoparticle. We did not find any obvious evidences of nano‐ T i O 2 particle skin penetration using several morphological methods after the subchronic exposure. We believe that the influence of subchronic exposure of T i O 2 is not significant based on our study.