Published online Feb 28, 2019. doi: 10.3748/wjg.v25.i8.955
Peer-review started: December 17, 2018
First decision: January 18, 2019
Revised: January 25, 2019
Accepted: January 28, 2019
Article in press: January 29, 2019
Published online: February 28, 2019
Processing time: 72 Days and 21.3 Hours
Procyanidins have beneficial effects on metabolic syndrome and antimicrobial activity, but the mechanisms underlying these effects are unclear.
To investigate the effects of procyanidin B2 (PB2) on non-alcoholic fatty liver disease and to explore the possible mechanism.
Thirty male New Zealand white rabbits were randomized into three groups. All of them were fed either a high-fat-cholesterol diet (HCD) or chow diet. HCD-fed rabbits were treated with vehicle or PB2 daily for 12 wk. Body weight and food intake were evaluated once a week. Serum biomarkers, such as total cholesterols, triglycerides, and aspartate transaminase, were detected. All rabbits were sacrificed and histological parameters of liver were assessed by hematoxylin and eosin-stained sections. Moreover, several lipogenic genes and gut microbiota (by 16S rRNA sequencing) were investigated to explore the possible mechanism.
The HCD group had higher body weight, liver index, serum lipid profile, insulin resistance, serum glucose, and hepatic steatosis compared to the CHOW group. PB2 treatment prevented HCD-induced increases in body weight and hypertriglyceridemia in association with triglyceride accumulation in the liver. PB2 also ameliorated low-grade inflammation, which was reflected by serum lipopolysaccharides and improved insulin resistance. In rabbit liver, PB2 prevented the upregulation of steroid response element binding protein 1c and fatty acid synthase and the downregulation of carnitine palmitoyltransferase, compared to the HCD group. Moreover, HCD led to a decrease of Bacteroidetes in gut microbiota. PB2 significantly improved the proportions of Bacteroidetes at the phylum level and Akkermansia at the genus level.
Our results indicate the possible mechanism of PB2 to improve HCD-induced features of metabolic syndrome and provide a new dietary supplement.
Core tip: Procyanidins are widely recognized for their excellent antioxidant properties and fewer side effects compared to other drugs. In the past, the mechanism of procyanidin to improve insulin resistance mainly focused on the antioxidant effect. The effect of procyanidin on non-alcoholic fatty liver disease is not clear. We found that procyanidin can reduce fatty liver by remodeling intestinal flora, decreasing endotoxemia, and down-regulating fatty acid synthesis genes. Our results open a new chapter in the mechanism of action of plant compounds and suggest a safer method for the treatment of non-alcoholic fatty liver disease.