The in vivo underlying mechanism for recovery response formation in nano-titanium dioxide exposed Caenorhabditis elegans after transfer to the normal condition

So far, we still know little about mechanism for recovery response of engineered nanomaterials (ENMs). Here we used Caenorhabditis elegans to investigate recovery responses of titanium dioxide nanoparticles (TiO2-NPs) exposed animals and the underlying mechanism. After acute exposure to TiO2-NPs (100 mg/L), endpoints including defecation and permeable state of intestinal barrier of exposed nematodes returned to control levels; however, after prolonged exposure to TiO2-NPs (100 μg/L), endpoints of exposed nematodes could not be recovered to control levels under the normal condition. After prolonged exposure to TiO2-NPs, nematodes exhibited severe deficits in development of intestinal barrier and AVL and DVB neurons controlling defecation; however, after acute exposure to TiO2-NPs, nematodes had normal developmental state of intestinal barrier and AVL and DVB neurons. Our results imply that developmental states of intestinal barrier and AVL and DVB neurons may serve as a pivotal determinant for recovery response in TiO2-NPs exposed nematodes.From the Clinical EditorThis basic science study investigates the recovery response to TiO2 nanoparticles in a nematode model, and concludes that developmental states of the intestinal barrier and AVL and DVB neurons likely serve as determinants for recovery following TiO2-NP exposure.

Graphic AbstractIn C. elegans, after prolonged exposure to high concentrations of TiO2-NPs, animals may meet difficulties to exhibit the recovery response under the normal condition. We raised a hypothesis that both defecation behavior and intestinal barrier contribute greatly to the recovery response formation for TiO2-NPs exposed animals. Structural state of both neurons controlling defecation behavior and intestinal barrier may play a pivotal role in regulating the recovery response formation in TiO2-NPs exposed animals under the normal condition.Figure optionsDownload high-quality image (158 K)Download as PowerPoint slide