title: Biosafety assessment of titanium dioxide nanoparticles in acutely exposed nematode Caenorhabditis elegans with mutations of genes required for oxidative stress or stress response.
abstract: We used Caenorhabditis elegans to investigate whether acute exposure to TiO2-NPs at the concentration of 20 μg L(-1) reflecting predicted environmental relevant concentration and 25 mg L(-1) reflecting concentration in food can cause toxicity on nematodes with mutations of susceptible genes. Among examined mutants associated with oxidative stress and stress response, we found that genes of sod-2, sod-3, mtl-2, and hsp-16.48 might be susceptible for TiO2-NPs toxicity. Mutations of these genes altered functions of both possible primary and secondary targeted organs in nematodes exposed to 25 mg L(-1) of TiO2-NPs for 24-h. Mutations of these genes caused similar expression patterns of genes required for oxidative stress in TiO2-NPs exposed mutant nematodes, implying their similar mechanisms to form the susceptible property. Nevertheless, acute exposure to 20 μg L(-1) of TiO2-NPs for 24-h and 25 mg L(-1) of TiO2-NPs for 0.48-h or 5.71-h did not influence functions of both possible primary and secondary targeted organs in sod-2, sod-3, mtl-2, and hsp-16.48 mutants. Therefore, our results suggest the relatively safe property of acute exposure to TiO2-NPs with certain durations at predicted environmental relevant concentrations or concentrations comparable to those in food in nematodes with mutations of some susceptible genes.
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; Environmental Medicine Engineering in Ministry of Education, Medical School of Southeast University, Nanjing 210009, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Rui
authors.forename: Yunli
authors.initials: Y
authors.lastname: Zhao
authors.forename: Qiuli
authors.initials: Q
authors.lastname: Wu
authors.forename: Meng
authors.initials: M
authors.lastname: Tang
authors.forename: Dayong
authors.initials: D
authors.lastname: Wang
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000235:genetics; D009154:Mutation; D053758:Nanoparticles / Q000633:toxicity*; D018384:Oxidative Stress / Q000235:genetics*; D018570:Risk Assessment; D014025:Titanium / Q000633:toxicity*; D023382:Toxicity Tests, Acute
chemical_list: C009495:titanium dioxide; D014025:Titanium
keywords: Acute exposure; Caenorhabditis elegans; Susceptible gene; TiO(2)-NPs; Toxicity assessment