title: Distribution and histologic effects of intravenously administered amorphous nanosilica particles in the testes of mice.
abstract: Amorphous nanosilica particles (nSP) are being utilized in an increasing number of applications such as medicine, cosmetics, and foods. The reduction of the particle size to the nanoscale not only provides benefits to diverse scientific fields but also poses potential risks. Several reports have described the in vivo and in vitro toxicity of nSP, but few studies have examined their effects on the male reproductive system. The aim of this study was to evaluate the testicular distribution and histologic effects of systemically administered nSP. Mice were injected intravenously with nSP with diameters of 70 nm (nSP70) or conventional microsilica particles with diameters of 300 nm (nSP300) on two consecutive days. The intratesticular distribution of these particles 24h after the second injection was analyzed by transmission electron microscopy. nSP70 were detected within sertoli cells and spermatocytes, including in the nuclei of spermatocytes. No nSP300 were observed in the testis. Next, mice were injected intravenously with 0.4 or 0.8 mg nSP70 every other day for a total of four administrations. Testes were harvested 48 h and 1 week after the last injection and stained with hematoxylin-eosin for histologic analysis. Histologic findings in the testes of nSP70-treated mice did not differ from those of control mice. Taken together, our results suggest that nSP70 can penetrate the blood-testis barrier and the nuclear membranes of spermatocytes without producing apparent testicular injury.
authors.affiliation: Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Morishita
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Satoh
authors.forename: Nao
authors.initials: N
authors.lastname: Nojiri
authors.forename: Kazuya
authors.initials: K
authors.lastname: Nagano
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Abe
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Kamada
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Tsunoda
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nabeshi
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Tsutsumi
mesh_terms: D000818:Animals; D007275:Injections, Intravenous; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000008:administration & dosage*; D010316:Particle Size; D012822:Silicon Dioxide / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D013737:Testis / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D012822:Silicon Dioxide