Protective effects of grape seed procyanidin extract on intestinal barrier dysfunction induced by a long-term high-fat diet

Grape seed procyanidin extract (GSPE) can modulate intestinal dysfunction, however; the mechanism needs to be clarified. This study aims at investigating the beneficial effect of GSPE on intestinal epithelial integrity and its regulatory mechanism. The results showed that consumption of high-fat (HF) diet for 13 weeks increased intestinal permeability. GSPE (200 mg/kg.bw) treatment reduced the concentration of lipopolysaccharide (LPS) in the circulatory system. The expression of tight junction proteins increased in GSPE-treated rats. Moreover, GSPE treatment inhibited the expression of pro-inflammatory mediators. The flow cytometry results revealed that GSPE treatment significantly increased the proportion of CD4(+) CD25(+) Foxp3(+) Tregs in gut-associated lymphoid tissue. GSPE modulated the composition of the gut microbiota and Spearman's correlation analysis revealed that the genera Anaerotruncus, Blautia, Oscillibacter, and Ruminococcaceae UCG-004 were related to intestinal permeability indices. In conclusion, GSPE ameliorated intestinal barrier dysfunction in HF diet-fed rats, probably via the regulation of intestinal immune balance and intestinal microbiota.