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

Nabeshi H, Yoshikawa T, Akase T, Yoshida T, Tochigi S, Hirai T, Uji M, Ichihashi K, Yamashita T, Higashisaka K, Morishita Y, Nagano K, Abe Y, Kamada H, Tsunoda S, Itoh N, Yoshioka Y, Tsutsumi Y - Nanoscale Res Lett (2011)

Bottom Line: 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.These results indicated that nSP did not cause differentiation of osteoclasts.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan. tomoaki@phs.osaka-u.ac.jp.

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.

No MeSH data available.


Related in: MedlinePlus

Effect of silica particles on cytotoxicity. The cytotoxicity of RAW264.7 cells after incubation with nSP70, nSP300 or mSP1000 for 5 days was evaluated using the WST-8 assay. The percentage increase in cytotoxicity was calculated relative to the negative control. Data are expressed as the mean ± SD (n = 3). *P < 0.05, **P < 0.01 vs non-treated.
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Figure 1: Effect of silica particles on cytotoxicity. The cytotoxicity of RAW264.7 cells after incubation with nSP70, nSP300 or mSP1000 for 5 days was evaluated using the WST-8 assay. The percentage increase in cytotoxicity was calculated relative to the negative control. Data are expressed as the mean ± SD (n = 3). *P < 0.05, **P < 0.01 vs non-treated.

Mentions: To evaluate the cytotoxicity induced by silica particle treatment of the mouse macrophage cell line RAW264.7 cells, a WST-8 cell proliferation assay was carried out. The results showed that 30 μg/ml of nSP300 and mSP1000 treatment for 5 days did not induce cytotoxicity in RAW264.7 cells. In contrast, nSP70 treatment induced higher cytotoxicity (about 40% viability of non-treated cells) at 30 μg/ml, although 10 μg/ml of nSP70 treatment produced only marginal cytotoxicity (Figure 1). These results indicated that decreasing the silica particle size to below 100 nm increased the cytotoxicity significantly. We have confirmed that the number of silica particles ingested by cells increases as the particle size decreases, and only nSP70 invaded into the nuclei of dendritic cells which, along with macrophages, have a phagocytic capacity [15]. We also found that only nSP70 invaded into the nucleus, in other words the intracellular localization of nSP70 differed from that of nSP300 and mSP1000 [15]. From these results, it was suspected that differences in the number of ingested silica particles and/or in their intracellular localization were significant factors in their observed cytotoxicity in RAW264.7 cells. Results of this experiment confirmed that not all silica particles induced cytotoxicity at 10 μg/ml in RAW264.7 cells, and therefore subsequent studies were carried out at 10 μg/ml silica particle treatment.


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

Nabeshi H, Yoshikawa T, Akase T, Yoshida T, Tochigi S, Hirai T, Uji M, Ichihashi K, Yamashita T, Higashisaka K, Morishita Y, Nagano K, Abe Y, Kamada H, Tsunoda S, Itoh N, Yoshioka Y, Tsutsumi Y - Nanoscale Res Lett (2011)

Effect of silica particles on cytotoxicity. The cytotoxicity of RAW264.7 cells after incubation with nSP70, nSP300 or mSP1000 for 5 days was evaluated using the WST-8 assay. The percentage increase in cytotoxicity was calculated relative to the negative control. Data are expressed as the mean ± SD (n = 3). *P < 0.05, **P < 0.01 vs non-treated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211885&req=5

Figure 1: Effect of silica particles on cytotoxicity. The cytotoxicity of RAW264.7 cells after incubation with nSP70, nSP300 or mSP1000 for 5 days was evaluated using the WST-8 assay. The percentage increase in cytotoxicity was calculated relative to the negative control. Data are expressed as the mean ± SD (n = 3). *P < 0.05, **P < 0.01 vs non-treated.
Mentions: To evaluate the cytotoxicity induced by silica particle treatment of the mouse macrophage cell line RAW264.7 cells, a WST-8 cell proliferation assay was carried out. The results showed that 30 μg/ml of nSP300 and mSP1000 treatment for 5 days did not induce cytotoxicity in RAW264.7 cells. In contrast, nSP70 treatment induced higher cytotoxicity (about 40% viability of non-treated cells) at 30 μg/ml, although 10 μg/ml of nSP70 treatment produced only marginal cytotoxicity (Figure 1). These results indicated that decreasing the silica particle size to below 100 nm increased the cytotoxicity significantly. We have confirmed that the number of silica particles ingested by cells increases as the particle size decreases, and only nSP70 invaded into the nuclei of dendritic cells which, along with macrophages, have a phagocytic capacity [15]. We also found that only nSP70 invaded into the nucleus, in other words the intracellular localization of nSP70 differed from that of nSP300 and mSP1000 [15]. From these results, it was suspected that differences in the number of ingested silica particles and/or in their intracellular localization were significant factors in their observed cytotoxicity in RAW264.7 cells. Results of this experiment confirmed that not all silica particles induced cytotoxicity at 10 μg/ml in RAW264.7 cells, and therefore subsequent studies were carried out at 10 μg/ml silica particle treatment.

Bottom Line: 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.These results indicated that nSP did not cause differentiation of osteoclasts.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan. tomoaki@phs.osaka-u.ac.jp.

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.

No MeSH data available.


Related in: MedlinePlus