Dietary fish oil reverses lipotoxicity, altered glucose metabolism, and nPKC ε translocation in the heart of dyslipemic insulin-resistant rats

Abstract

The present study analyzes several markers of energy metabolism in the heart muscle of dyslipemic insulin-resistant rats fed a sucrose-rich diet (SRD, 62.5% wt/wt) for 8 months. It also explores the possible beneficial effects of dietary fish oil supplementation on cardiac lipids and glucose metabolism. With this purpose, male Wistar rats were fed an SRD for 6 months. Whereas half of the animals continued with the same diet for up to 8 months, the other half was fed an SRD in which fish oil (7% + 1% corn oil wt/wt) replaced corn oil (8% wt/wt) from months 6 to 8. The results were compared with rats fed a control diet (starch 62.5% wt/wt). The cardiac muscle of SRD-fed rats showed (1) a significant reduction ( P < .05) in key enzymes activities and metabolites involved in glucose metabolism, accompanied by a significant ( P < .05) increase of lipid storage (triglyceride, long-chain acyl coenzyme A, and diacylglycerol), and (2) a significant increase ( P < .05) of nPKC ε protein mass expression in the membrane fraction without changes in the cPKC βII. Dietary fish oil, which reduces the availability of plasma lipid flux and normalizes glucose homeostasis, was able to reverse heart muscle lipotoxicity. Fish oil benefits key enzymes activities in glucose metabolism and normalizes glycogen and glucose-6-phosphate concentration, and the altered nPKC ε protein mass expression translocation in the heart of SRD-fed rats. Our findings suggest that manipulation of dietary fats may play a key role in the management of lipid disorders, offering a protection against the development of cardiovascular diseases.