Abstract: With an increasing incidence rate，ulcerative colitis (UC) is an idiopathic inflammation of the colon causing diarrhea and blood in the stool. Existing studies have shown that oxidative stress is an important factor leading to UC, while superoxide dismutase (SOD) has a certain effect on relieving UC symptoms. To improve its bioavailability, superoxide dismutase (SOD) was self-assembled into nanoparticles (ΔSOD) by heating it. The activity, transmembrane capacity and radical scavenging capacity of ΔSOD were significantly better than those of native SOD. ΔSOD liposomes (L-ΔSOD) were prepared by reverse-phase evaporation and orally administered to mice with UC. The results showed that compared with the positive control and model groups, L-ΔSOD significantly ameliorated UC, reduced disease activity index (DAI) score, restored the morphology of colon tissue, increased the length of colon, reduced the density of colon and spleen coefficient, and restored the integrity of mucosal epithelium. Besides, L-ΔSOD could reduce the contents of malondialdehyde (MDA) and pro-inflammatory factors in colon tissue and increase the levels of glutathione peroxidase (GSH-Px) and tight junction protein mRNA expression. These results confirmed that oral L-ΔSOD has a good ameliorative effect on UC, which will lay the foundation for the application of SOD in promoting human health.

Key words: ulcerative colitis; superoxide dismutase; nanoparticles; liposome; antioxidant