Decaffeinated coffee consumption induces expression of tight junction proteins in high fat diet fed rats

Abstract

Background: Recent evidence indicates that gut microbiota plays a key role in the development of NAFLD through the gut-liver axis. An altered gut permeability induced by alterations of tight junction (TJ) proteins allows the passage of bacteria and substances leading to liver inflammation, hepatocyte damage and fibrosis. This study aims to evaluate the influence of decaffeinated coffee on gut permeability in a rat model of fat liver damage induced by a high fat diet (HFD). Methods: Twelve male Wistar rats were assigned to 3 groups. The first group received HFD for 5 months and drank water. The second group received HFD for 5 months and drank water added with 1.2mL decaffeinated coffee/day starting from the 4th month. The third group received standard diet (SD) and drank water. Protein and mRNA expression levels of Toll-Like Receptor-4 (TLR-4), Occludin and Zonula occludens-1 (ZO-1) were assessed in rat intestines. Results: A significant reduction of Occludin and ZO-1 was observed in HFD fed rats (0.97±0.05 vs 0.15±0.08 p<0.01, and 0.97±0.05 vs 0.57±0.14 p<0.001 respectively. This reduction was reverted in HFD+COFFEE rats (0.15±0.08 vs 0.83±0.27 p<0.01 and 0.57±0.14 vs 0.85±0.12 p<0.01 respectively). The TLR-4 expression up-regulated by HFD was partially reduced by coffee administration. Conclusions: HFD impairs the intestinal TJ barrier integrity. Coffee increases the expression of TJ proteins, reverting the altered gut permeability and reducing TLR-4 expression.