Hollow cerium nanoparticles synthesized by one-step method for multienzyme activity to reduce colitis in mice.

Background: Inflammatory bowel disease (IBD) is a common chronic intestinal inflammatory disease. High oxidative stress is a treatment target for IBD. Cerium oxide (CeO₂) nanomaterials as nanozymes with antioxidant activity are potential drugs for the treatment of colitis.

Aim: To synthesize hollow cerium (H-CeO₂) nanoparticles by one-step method and to validate the therapeutic efficacy of H-CeO₂ in IBD.

Methods: H-CeO₂ was synthesized by one-step method and examined its characterization and nanoenzymatic activity. Subsequently, we constructed dextran sulfate sodium (DSS)-induced colitis in mice to observe the effects of H-CeO₂ on colonic inflammation. The effects of H-CeO₂ on colon inflammation and reactive oxygen species (ROS) levels in IBD mice were detected by hematoxylin and eosin staining and dichlorofluorescein diacetate staining, respectively. Finally, the biological safety of H-CeO₂ on mice was evaluated by hematoxylin and eosin staining, blood routine, and blood biochemistry.

Results: H-CeO₂ nanoparticles prepared by the one-step method were uniform, monodisperse and hollow. H-CeO₂ had a good ability to scavenge ROS, ∙OH and ∙OOH. H-CeO₂ reduced DSS-induced decreases in body weight and colon length, colonic epithelial damage, inflammatory infiltration, and ROS accumulation. H-CeO₂ administration reduced the disease activity index of DSS-induced animals from about 8 to 5. H-CeO₂ had no significant effect on body weight, total platelet count, hemoglobin, white blood cell, and red blood cell counts in healthy mice. No significant damage to major organs was observed in healthy mice following H-CeO₂ administration.

Conclusion: The one-step synthesis of H-CeO₂ nanomaterials had good antioxidant activity, biosafety, and inhibited development of DSS-induced IBD in mice by scavenging ROS.