Aluminum nanoparticle exposure in L1 larvae results in more severe lethality toxicity than in L4 larvae or young adults by strengthening the formation of stress response and intestinal lipofuscin accumulation in nematodes

Toxicity of Al2O3-NPs, as compared to that of Al2O3, to L1-larval, L4-larval or young adult nematodes was evaluated. When exposure was performed at L1-larval stage, the significant increases of lethality, stress response, and intestinal lipofuscin autofluorescence were observed in 6.3–203.9 mg/L of Al2O3-NPs exposed nematodes. In contrast, when exposure was performed at L4-larval or young adult stage, the significant increases of lethality and intestinal lipofuscin autofluorescence were observed in 12.7–203.9 mg/L of Al2O3-NPs exposed nematodes, and the significant inductions of stress response were detected in 25.5–203.9 mg/L of Al2O3-NPs exposed nematodes. Moreover, the lethality was significantly correlated with the stress response and the intestinal lipofuscin autofluorescence in Al2O3-NPs exposed nematodes. These data imply that Al2O3-NPs exposure in L1 larvae causes more severe lethality toxicity than in L4 larvae or young adults by strengthening the formation of stress response and intestinal lipofuscin accumulation in nematodes.