Targeted proteomic analysis reveals that crocodile oil from <i>Crocodylus siamensis</i> may enhance hepatic energy metabolism in rats

Abstract

The liver is a key organ governing body energy metabolism. Dietary fats influence energy metabolism and mitochondrial functioning. Crocodile oil (CO) is rich in mono-and poly-unsaturated fatty acids that contain natural anti-inflammatory and healing properties. Our study examined how crocodile oil (CO) affects the expressions of liver proteins involved in energy metabolism in rats. Twenty-one male Sprague Dawley rats were divided into three groups and underwent oral gavage of 3 mL/kg of sterile water (N), CO (CO), or palm oil (PO) for 7 weeks. Body weight, energy intake, liver weight, liver indexes, blood lipid profiles, and liver-energy intermediates were measured. Liver proteome was analyzed using shotgun proteomics, and the functions and network interactions of several candidate proteins were predicted using STITCH v.5.0 software. Body weights, energy intake, liver contents, and lipid profiles did not differ between the groups. However, hepatic oxaloacetate and malate levels were significantly higher in the CO group than in the PO group. Targeted proteomics reveals that twenty-two from 1790 unique proteins in the CO group were involved in energy-generating pathways, including the tricarboxylic acid cycle and oxidative phosphorylation (OXPHOS), and were correlated with AMP-activated protein kinase signaling pathway. Cluster analysis of 59 differentially expressed proteins showed that OXPHOS-associated proteins were upregulated in the CO group, and three glycolytic metabolism-related proteins were downregulated in the CO group. CO may enhance hepatic energy metabolism by regulating the expressions of energy expenditure-related proteins.