Cyanidin-3,5-O-Glucoside Alleviates DSS-Induced Colon Barrier Dysfunction and Fibrosis Through Autophagy-Associated Pathway-Mediated Inflammation Repression in a C57BL/6J Mouse Model.

Abstract

The aim of the present study was to investigate the effects of cyanidin-3,5-O-glucoside (C35G) on intestinal inflammation, mucosal barrier integrity, and fibrogenesis in a dextran sodium sulfate (DSS, 2.5%)-induced mouse model of ulcerative colitis (UC), as well as to elucidate the mechanisms underlying its effects. After a 28-day C35G intervention, UC mice showed significant improvements in clinical symptoms, including weight loss and an increased disease activity index (DAI). Additionally, there was an elevation in serum levels of inflammatory factors such as IL-1β, IL-6, IL-17 A, IL-18, and TNF-α. C35G increased the colonic mRNA levels of Zo1, Claudin1, and Occludin, and reduced intestinal epithelial permeability, ultimately promoting the restoration of mucosal barrier integrity in UC mice. In addition, C35G influenced the colonic Nrf2/Keap1 pathway by upregulating the mRNA levels of Cat, Sod1, Sod2, and Mgst1. This modulation was accompanied by an increase in the serum levels of SOD and catalase, as well as a reduction in the levels of the oxidative stress marker MDA. The C35G-induced inhibition of NLRP3 inflammasome activation reduced the expression of intestinal fibrotic factors (α-SMA and Collagen I), ultimately attenuating intestinal fibrosis. Moreover, C35G stimulated autophagy in the intestinal epithelial tissues of UC mice by increasing the protein expression of LC3-II, Beclin 1, p-AMPK, and ULK1 while decreasing the levels of p62, p-Akt, and p-mTOR. These results suggested that C35G reduces oxidative stress and inflammation by acting as an antioxidant and modulating the Nrf2/Keap1 pathway. Additionally, C35G regulates autophagy through the AMPK/Akt/mTOR/ULK1 pathway, thereby improving intestinal inflammation, restoring the compromised intestinal barrier, and preventing intestinal fibrosis in mice with UC.