Targeting Hepatic Protein Carbonylation and Oxidative Stress Occurring on Diet-Induced Metabolic Diseases through the Supplementation with Fish Oils

Abstract

The present study addressed the ability of long-chain ω-3 polyunsaturated fatty acids (ω-3 PUFA), i.e., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), to ameliorate liver protein damage derived from oxidative stress and induced by consumption of high-caloric diets, typical of Westernized countries. The experimental design included an animal model of Sprague-Dawley rats fed high-fat high-sucrose (HFHS) diet supplemented with ω-3 EPA and DHA for a complete hepatic proteome analysis to map carbonylated proteins involved in specific metabolic pathways. Results showed that the intake of marine ω-3 PUFA through diet significantly decreased liver protein carbonylation caused by long-term HFHS consumption and increased antioxidant system. Fish oil modulated the carbonylation level of more than twenty liver proteins involved in critical metabolic pathways, including lipid metabolism (e.g., albumin), carbohydrate metabolism (e.g., pyruvate carboxylase), detoxification process (e.g., aldehyde dehydrogenase 2), urea cycle (e.g., carbamoyl-phosphate synthase), cytoskeleton dynamics (e.g., actin), or response to oxidative stress (e.g., catalase) among others, which might be under the control of diet marine ω-3 PUFA. In parallel, fish oil significantly changed the liver fatty acid profile given by the HFHS diet, resulting in a more anti-inflammatory phenotype. In conclusion, the present study highlights the significance of marine ω-3 PUFA intake for the health of rats fed a Westernized diet by describing several key metabolic pathways which are protected in liver.

Keywords: Sprague-Dawley rat; carbonylation; fish oils; high-fat high-sucrose diet; liver protein damage; marine omega-3 fatty acids; oxidative stress.

Figure 1

Protein carbonylation index: (A) total protein carbonylation index in liver from STD, HFHS and HFHS + ω3-fed rats; and (B) plasma albumin carbonylation index from STD, HFHS and HFHS + ω3-fed rats. Data are presented as mean ± standard deviation. * Pb.05, ** Pb.01.

Figure 2

(A) 1-D FTSC-stained gel of liver proteins. Dietary groups: (a) STD; (b) HFHS; and (c) HFHS + ω3. Marked bands (b1–b7) showed differential protein carbonylation index. (B) 1-D Coomassie-stained gel of liver proteins. Dietary groups: (a) STD; (b) HFHS; and (c) HFHS + ω3. Marked bands (b1–b7) showed differential protein carbonylation index.

Figure 3

2-D FTSC-stained and Coomassie gels of liver proteins. Dietary groups: (a) STD; (b) HFHS; and (c) HFHS + ω3. Numbered protein spots represent carbonylated proteins confidently identified.

Figure 4

Gene ontology (GO) of carbonylated proteins from liver of both STD and HFHS diets: (a) cellular distribution; (b) molecular function; (c) protein class; and (d) biological process of carbonylated proteins.

Figure 5

Network analysis of carbonylated proteins from the liver of both STD and HFHS diets. Graphic representation of the network of connections of all proteins that appear carbonylated and were identified in liver.