Preventive effect of Chinese dwarf cherry [Cerasus humilis (Bge.) Sok.] fermentation juice on dextran sulfate sodium-induced ulcerative colitis rats through the regulation of IgA and the intestinal immune barrier

Ulcerative colitis (UC) is a modern, refractory disease, and studies have shown that UC is closely associated with the gut microbiota and intestinal immune barrier. This study evaluated the protective effects and regulatory mechanism of Chinese dwarf cherry [Cerasus humilis (Bge.) Sok.] fermentation juice (CFJ) on UC induced by dextran sulfate sodium (DSS). The results indicated that CFJ could significantly modulate the oxidative stress index in the serum and colon, observably reduce MPO and NO activity, and increase the SOD level. CFJ significantly downregulated the levels of TNF-α, IL-1β and IL-6 and reduced inflammation caused by DSS. SIgA and short-chain fatty acids (SCFAs) levels were effectively improved in the CFJ group, especially the acetic acid and butyric acid levels. Intestinal flora analysis showed that DSS could enrich harmful bacteria such as Alistipes and Oribacterium and that CFJ could increase the abundance of beneficial bacteria (Parasutterella, Bacteroides, Roseburia and Blautia). SIgA in the colon was positively correlated with Lachnoclostridium, Blautia, Lachnospiraceae_UCG-004, Prevotellaceae_NK3B31_group and other beneficial bacteria. The results showed that DSS group rats had immunity and signalling pathway disorders and that CFJ could regulate immune disorders, mainly by regulating the expression of IgA pathway components. Taken together, our results demonstrated that CFJ could regulate changes in the gut microbiota, improve the expression of immune protein-related genes, further regulate intestinal mucosal immune function and maintain intestinal mucosal barrier homeostasis.