title: In vivo effect of industrial titanium dioxide nanoparticles experimentally exposed to hairless rat skin.
abstract: We morphologically investigated animal skin exposed to W/O emulsion containing 10 wt % ultrafine TiO(2) particles that had been characterized. After 4 h, exposed skin was investigated by light microscopy, confocal laser scanning microscopy (CLSM) and electron microscopy with energy-dispersive X-ray spectrometry (EDX). Light microscopic evaluation was also performed on the exposed skin after 24, 72 and 168 h. Light microscopy did not show any morphological and immunohistochemical changes in the skin. Electron microscopy revealed that the most TiO(2) particles were localized in the interfollicular stratum disjunctum and the keratinized layer of follicular infundibulum. No TiO(2) particles were detected in the viable skin, which was confirmed by EDX. Furthermore, we demonstrated a specific TiO(2) affinity to the follicular opening area by light microscopy and low-vacuum scanning electron microscopy with EDX. Our study suggests that TiO(2) particles neither penetrate into viable cell layers nor biologically cause any cellular changes.
authors.affiliation: Division of Dermatology, Department of Medicine of Sensory and Motor Organs, Tottori University Faculty of Medicine, Yonago, Japan. koujiadachi@grape.med.tottori-u.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Adachi
authors.forename: Nanako
authors.initials: N
authors.lastname: Yamada
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D006197:Hair; D006801:Humans; D008297:Male; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000033:anatomy & histology / Q000187:drug effects* / Q000378:metabolism; D014025:Titanium / Q000737:chemistry / Q000633:toxicity*
chemical_list: C009495:titanium dioxide; D014025:Titanium