Hollow Ce[O.sub.2] with ROS-Scavenging Activity to Alleviate Colitis in Mice

Introduction: Excessive production of reactive oxygen species (ROS) to induce high oxidative stress is one of the main causes of colitis; thus, it has been regarded as a therapeutic target for colitis treatment. And the nanomaterial-based therapeutic strategies are effective against colitis. However, the previous elaborately designed materials exhibit limited application due to the uncertain biocompatibility and complicated manufacturing processes. Methods: In this study, the highly monodisperse hollow Ce[O.sub.2] nanoparticles (H-Ce[O.sub.2]) with uniform morphology were obtained by in situ growing Ce[O.sub.2] on solid silica nanoparticles and subsequently removing the silica core. The H-Ce[O.sub.2] was further modified with PEG, which owned excellent biological stability and biocompatibility. The experimental model of colitis induced by dextran sulfate sodium (DSS) was used to investigate the anti-inflammatory effect of H-Ce[O.sub.2]-PEG. Results: The H-Ce[O.sub.2]-PEG showed good ROS scavenging efficacy and decreased the levels of proinflammatory cytokines (IL-6, IL-1[beta], IL-18, and TNF-[alpha]) in DSS-induced colitis mice. Furthermore, H-Ce[O.sub.2]-PEG inhibited the activation of the MAPK signalling pathway to alleviate colitis. Conclusion: This study reveals the therapeutic effects of Ce[O.sub.2]-based nanomedicine toward colitis and elucidates the specific signalling pathway involved, which provides potential alternative therapeutic options for patients with inflammation tissue. Keywords: hollow Ce[O.sub.2], ROS, inflammation, colitis, MAPK signalling pathway