Open Access Nano Express

Effect of amorphous silica nanoparticles on in vitro RANKL-induced osteoclast differentiation in murine macrophages

Hiromi Nabeshi12, Tomoaki Yoshikawa12*, Takanori Akase12, Tokuyuki Yoshida12, Saeko Tochigi12, Toshiro Hirai12, Miyuki Uji12, Ko-ichi Ichihashi12, Takuya Yamashita12, Kazuma Higashisaka12, Yuki Morishita12, Kazuya Nagano2, Yasuhiro Abe2, Haruhiko Kamada23, Shin-ichi Tsunoda234, Norio Itoh12, Yasuo Yoshioka23 and Yasuo Tsutsumi123*

Author Affiliations

1 Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan

2 Laboratory of Biopharmaceutical Research (Pharmaceutical Proteomics), National Institute of Biomedical Innovation, 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan

3 The Center for Advanced Medical Engineering and Informatics, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan

4 Laboratory of Biomedical Innovation, Graduate School of Pharmaceutical Sciences, Osaka University, 7-6-8 Saito-Asagi, Ibaraki, Osaka, 567-0085, Japan

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Nanoscale Research Letters 2011, 6:464  doi:10.1186/1556-276X-6-464

Published: 22 July 2011

Abstract

Amorphous silica nanoparticles (nSP) have been used as a polishing agent and/or as a remineralization promoter for teeth in the oral care field. The present study investigates the effects of nSP on osteoclast differentiation and the relationship between particle size and these effects. Our results revealed that nSP exerted higher cytotoxicity in macrophage cells compared with submicron-sized silica particles. However, tartrate-resistant acid phosphatase (TRAP) activity and the number of osteoclast cells (TRAP-positive multinucleated cells) were not changed by nSP treatment in the presence of receptor activator of nuclear factor κB ligand (RANKL) at doses that did not induce cytotoxicity by silica particles. These results indicated that nSP did not cause differentiation of osteoclasts. Collectively, the results suggested that nanosilica exerts no effect on RANKL-induced osteoclast differentiation of RAW264.7 cells, although a detailed mechanistic examination of the nSP70-mediated cytotoxic effect is needed.

Keywords:
silicon dioxide; nanoparticle; osteoclast differentiation