Oxidative DNA damage in rat lung after exposure to cerium oxide nanoparticles

Abstract

Oxidative stress is an intermediate step that leads to lung damage, and consequently to various disease states. Recently, considerable interest has been focused on the health effects of industrial nanomaterials, and several mechanisms underlying their adverse health effects have been proposed. Among them, oxidative stress is considered to be one of the most important. 8-Hydroxy-2′-deoxyguanosine (8-OHdG) is a major type of oxidative DNA damage, and is often analyzed as a marker of oxidative stress in human and animal studies. The aim of this work was to examine whether oxidative DNA damage occurs in rat lungs exposed to cerium dioxide (CeO2) nanoparticles. To detect oxidative DNA damage in the rat lung, the 8-OHdG levels in the lung DNA were analyzed by HPLC with electrochemical detection. As a result, the 8-OHdG levels in the lung DNA were significantly higher in the 1 mg CeO2 nanoparticle intratracheal injection groups than the vehicle-injected control groups, at 1 week and 1 month after injection. In addition, the 8-OHdG level of the CeO2 nanoparticle inhalation group was significantly increased at 3 days after exposure. Both effects were dose-dependent. These results indicated that exposure to CeO2 nanoparticles might cause adverse health effects in the lung. This work is partially supported by “Development of innovative methodology for safety assessment of industrial nanomaterials” by Ministry of Economy, Trade and Industry (METI) of Japan.