Abstract:Exosome secretion by IEC-6 intestinal epithelial cells was induced by Dendrobium officinale polysaccharide (DOP) to investigate the TNF-α-induced protective effect of the small intestinal epithelial barrier. The secreted exosomes were extracted by ultracentrifugation. The morphology of exosomes was observed by transmission electron microscopy, the marker proteins HSP70, TSG101, and CD63 were detected by western blot, and the particle sizes of exosomes were determined by nanoparticle tracking analysis. The effects of DOP on the expression of tight junction proteins in intestinal epithelial tissues were clarified by western blot. The activities of glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), and catalase (CAT) were measured. The effects of DOP on the expression of tight junction proteins in the intestinal epithelium were detected by Western blot, and the activities of oxidative stress kinase GSH-PX, SOD, and CAT were determined. The results showed that the particles were disc-shaped (diameter: 30~150 nm) and contained the signature proteins TSG101, HSP70, and CD63. The particles were identified as exosomes. The exosome DE produced by DOP incubation can be taken up by IEC-6 cells. The expression of ZO-1, Occludin, and MUC1 proteins in IEC-6 cells of mice in the DOP group increased by 104.63%, 70.09%, and 52.34%, respectively. The activities of antioxidant enzymes SOD, CAT, and GSH-PX were increased by 52.16%, 43.40%, and 122.89%, respectively. In summary, DOP can improve the antioxidant enzyme activity and enhance the expression of tight junction proteins in intestinal epithelial cells through exosomes to repair intestinal barrier damage.
