Pretreatment with paeonol prevents the adverse effects and alters the translocation of multi-walled carbon nanotubes in nematode Caenorhabditis elegans

Paeonol is a natural compound isolated from the root bark of Moutan. In this study, we employed the in vivo assay system of Caenorhabditis elegans to investigate the possible beneficial effects of paeonol against the toxicity of multi-walled carbon nanotubes (MWCNTs). With the aid of lifespan, brood size, locomotion behavior, and intestinal reactive oxygen species (ROS) production as endpoints, we found that pretreatment with paeonol (300-500 mg L-1) inhibited the adverse effects of MWCNTs (100 mg L-1) on nematodes. Pretreatment with paeonol also suppressed the translocation of MWCNTs into the body through the intestinal barrier. Moreover, pretreatment with paeonol was helpful for maintaining normal intestinal permeability and prevented the formation of dysregulated expression patterns of genes required for intestinal development in MWCNT exposed nematodes. Pretreatment with paeonol further prevented the adverse effects of MWCNTs on defecation behavior and the development of AVL and DVB neurons controlling the defecation behavior in nematodes. Therefore, both the intestinal barrier and defecation behavior may contribute greatly to the formation of beneficial effects of paeonol against the toxicity of MWCNTs and the bioavailability of MWCNTs for nematodes. In addition, our data suggest that treatment with paeonol alone might have the lifespan-extending function in nematodes.