Comparative Pulmonary Toxicity of Two Ceria Nanoparticles with the Same Primary Size

• Main Authors: Lu Peng, Xiao He, Peng Zhang, Jing Zhang, Yuanyuan Li, Junzhe Zhang, Yuhui Ma, Yayun Ding, Zhenqiang Wu, Zhifang Chai, Zhiyong Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2014-04-01
• Series: International Journal of Molecular Sciences
• Subjects: nano-ceria; pulmonary toxicity; agglomerates; size distribution; surface chemistry
• Online Access: http://www.mdpi.com/1422-0067/15/4/6072

Ceria nanoparticles (nano-ceria) have recently gained a wide range of applications, which might pose unwanted risks to both the environment and human health. The greatest potential for the environmental discharge of nano-ceria appears to be in their use as a diesel fuel additive. The present study was designed to explore the pulmonary toxicity of nano-ceria in mice after a single exposure via intratracheal instillation. Two types of nano-ceria with the same distribution of a primary size (3–5 nm), but different redox activity, were used: Ceria-p, synthesized by a precipitation route, and Ceria-h, synthesized by a hydrothermal route. Both Ceria-p and Ceria-h induced oxidative stress, inflammatory responses and cytotoxicity in mice, but their toxicological profiles were quite different. The mean size of Ceria-p agglomerates was much smaller compared to Ceria-h, thereby causing a more potent acute inflammation, due to their higher number concentration of agglomerates and higher deposition rate in the deep lung. Ceria-h had a higher reactivity to catalyzing the generation of reactive oxygen species (ROS), and caused two waves of lung injury: bronchoalveolar lavage (BAL) inflammation and cytotoxicity in the early stage and redox-activity-evoked lipid peroxidation and pro-inflammation in the latter stage. Therefore, the size distribution of ceria-containing agglomerates in the exhaust, as well as their surface chemistry are essential characteristics to assess the potential risks of using nano-ceria as a fuel additive.