Effects of fish oil and grape seed extract combination on hepatic endogenous antioxidants and bioactive lipids in diet-induced early stages of insulin resistance in rats

Abstract

Diacylglycerols (DAG) and ceramides have been suggested as early predictors of insulinresistance. This study was aimed to examine the combined effects of fish oil (FO) and grape seedextract (GSE) on hepatic endogenous antioxidants, DAG and ceramides in diet-induced early stagesof insulin resistance. Thirty-five rats were fed one of the following diets: (1) a standard diet (STDgroup), (2) a high-fat high-sucrose diet (HFHS group), (3) an HFHS diet enriched with FO (FO group),(4) an HFHS diet enriched with GSE (GSE group) or (5) an HFHS diet enriched with FO and GSE(FO+GSE group). In the liver, endogenous antioxidants were measured using spectrophotometricand fluorometric techniques, and non-targeted lipidomics was conducted for the assessment of DAGand ceramides. After 24 weeks, the FO+GSE group showed increased glutathione peroxidaseactivity, as well as monounsaturated fatty acid and polyunsaturated fatty acid-containing DAG, andlong-chain fatty acid-containing ceramides abundances compared to the STD group. The FO and GSEcombination induced similar activation of the antioxidant system and bioactive lipid accumulation inthe liver than the HFHS diet without supplementation. In addition, the FO and GSE combinationincreased the abundances of polyunsaturated fatty acid-containing DAG in the liver.