Quercetin Protects Intestinal Barrier Integrity in Inflammation and Oxidative Stress

Area of Science:

• Gastroenterology
• Nutrition Science
• Molecular Biology

Background:

• Obesity-inducing diets cause gut inflammation, oxidative stress, and barrier dysfunction, increasing metabolic disorder risk.
• Understanding protective mechanisms against diet-induced gut damage is crucial for metabolic health.

Purpose of the Study:

• To investigate how quercetin protects intestinal integrity in mice consuming a high-fat diet (HFD).
• To elucidate the molecular mechanisms underlying quercetin's protective effects on the gut.

Main Methods:

• Mice were fed either a low-fat diet (LFD) or HFD, with or without quercetin supplementation.
• Evaluated intestinal gene/protein expression, microRNA levels, barrier permeability, and circulating biomarkers.

Main Results:

• Quercetin improved intestinal barrier integrity by 17% in HFD-fed mice, upregulating tight junction and mucin expression.
• Quercetin reduced NF-κB activation, increased NRF2-mediated antioxidant responses, and suppressed TLR4 signaling.
• It restored AMPK and sirtuin 1 levels, normalized short-chain fatty acid receptors and serotonin transporters, and improved plasma biomarkers of gut integrity.

Conclusions:

• Quercetin protects the intestinal epithelial barrier against HFD-induced inflammation and oxidative stress.
• Protection is mediated through AMPK-activated modulation of NF-κB and NRF2 signaling pathways.