EPA/DHA and linseed oil have different effects on liver and adipose tissue in rats fed with a high-fat diet

The incidence of cardiovascular diseases and metabolic disorders has increased worldwide. Clinical and experimental research has shown that the consumption of ω-3 FAs can be beneficial to metabolism in several ways, as they can act on metabolic pathways. Our objective was to evaluate the effect of treatment with linseed oil, a vegetable oil rich in alpha-linolenic acid, and EPA and DHA in different proportions (3:1 EPA:DHA, and 1:3 EPA:DHA), on the metabolic disorders induced by a high-fat diet (20 % lipids) in rats for 2 weeks, after 18 weeks of consumption of a high-fat diet. In 18 weeks, the high-fat diet increased blood glucose, systolic blood pressure, triglyceride concentration in the liver and adipose tissue, and impaired insulin sensibility without interfering in the weight of the animals. All treatments were effective in reducing the deposition of hepatic type III collagen, the proportion of ω-6/ω-3 in the liver and WAT (white adipose tissue), the proportion of area/number of adipocytes, and the gene expression of the ACC, FAS, and CPT1 enzymes. In addition, treatment with EPA and DHA reduced blood glucose, serum TNF-α concentration, amount of liver fat, degree of microsteatosis and type I collagen deposition in the liver, deposition of type I and III collagen in TA, gene expression of the transcription factor SREBP-1c, and increased hepatic binucleation. EPA in major proportion was more effective in reducing the area of adipocytes, hepatic triglyceride concentration, PPAR-α expression, and WAT fat weight. DHA in a major proportion reduced the concentration of MCP1 in WAT. LO treatment did not have any isolated effects. We concluded that EPA and DHA were more effective in treating metabolic damage than treatment with LO, leading to a more favorable metabolic profile.