title: Small sizes of TiO2-NPs exhibit adverse effects at predicted environmental relevant concentrations on nematodes in a modified chronic toxicity assay system.
abstract: In Caenorhabditis elegans, although acute toxicity of TiO(2) nanoparticles (TiO(2)-NPs) at high concentrations has been investigated, we still know little about chronic toxicity of TiO(2)-NPs. Our data here showed that acute TiO(2)-NPs exposure in the range of μg/L had no obviously adverse effects on nematodes, but the chronic toxicities of large sizes (60 nm and 90 nm) of TiO(2)-NPs in the range of μg/L were detected in nematodes in a modified chronic toxicity assay system. Moreover, chronic toxicities of small sizes (4 nm and 10nm) of TiO(2)-NPs in the range of ng/L were observed in nematodes with locomotion behavior and ROS production as endpoints. In nematodes chronically exposed to small sizes of TiO(2)-NPs at predicted environmental relevant concentrations, locomotion behavior was significantly (P<0.01) correlated with ROS production. Furthermore, treatment with antioxidants (ascorbate and N-acetyl-l-cysteine) inhibited both the induction of ROS production and the decrease of locomotion behaviors observed in nematodes chronically exposed to small sizes of TiO(2)-NPs at predicted environmental relevant concentrations. Therefore, chronic exposure to small sizes of TiO(2)-NPs at predicted environmental relevant concentrations can cause adverse effects on nematodes, and formation of such adverse effects may be largely due to the induction of oxidative stress.
authors.affiliation: Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Department of Biochemistry and Molecular Biology, Medical School of Southeast University, Nanjing 210009, China.
authors.forename: Qiuli
authors.initials: Q
authors.lastname: Wu
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Yinxia
authors.initials: Y
authors.lastname: Li
authors.forename: Yiping
authors.initials: Y
authors.lastname: Li
authors.forename: Boping
authors.initials: B
authors.lastname: Ye
authors.forename: Meng
authors.initials: M
authors.lastname: Tang
authors.forename: Dayong
authors.initials: D
authors.lastname: Wang
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D017173:Caenorhabditis elegans / Q000254:growth & development / Q000502:physiology*; D006128:Growth / Q000187:drug effects; D007202:Indicators and Reagents; D007422:Intestines / Q000187:drug effects / Q000254:growth & development; D009043:Motor Activity / Q000187:drug effects; D053758:Nanoparticles / Q000633:toxicity*; D018384:Oxidative Stress / Q000502:physiology; D010316:Particle Size; D017382:Reactive Oxygen Species / Q000378:metabolism; D013535:Suspensions; D014025:Titanium / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D007202:Indicators and Reagents; D017382:Reactive Oxygen Species; D013535:Suspensions; C009495:titanium dioxide; D014025:Titanium; D001205:Ascorbic Acid; D000111:Acetylcysteine