Colon-Targeted Release of Gel Microspheres Loaded with Antioxidative Fullerenol for Relieving Radiation-Induced Colon Injury and Regulating Intestinal Flora.

Radiation-induced colitis is a serious clinical problem worldwide. However, the current treatment options for this condition have limited efficacy and can cause side effects. To address this issue, colon-targeted fullerenol@pectin@chitosan gel microspheres (FPCGMs) are developed, which can aggregate on colon tissue for a long time, scavenge free radicals generated in the process of radiation, and regulate intestinal flora to mitigate damage to colonic tissue. First, FPCGMs exhibit acid resistance and colon-targeted release properties, which reduce gastrointestinal exposure and extend the local colonic drug residence time. Second, fullerenol, which has a superior scavenging ability and chemical stability, reduces oxidative stress in colonic epithelial cells. Based on this, it is found that FPCGMs significantly reduce inflammation in colonic tissue, mitigated damage to tight junctions of colonic epithelial cells, and significantly relieved radiation-induced colitis in mice. Moreover, 16S ribosomal DNA (16S rDNA) sequencing results show that the composition of the intestinal flora is optimized after FPCGMs are utilized, indicating that the relative abundance of probiotics increases while harmful bacteria are inhibited. These findings suggest that it is a promising candidate for treating radiation-induced colitis.