The Metabolic Syndrome of ω3-Depleted Rats. VIII. Dietary Lipid-Induced Liver Steatosis

ABSTRACT

The present study aims at investigating the determinants of the undesirable aggravation of liver steatosis observed in rats first deprived, for 7 months from the 6^th week after birth onwards, of a dietary supply of long-chain polyunsaturated ω3 fatty acids by exposure to a 5% sunflower oil-containing diet and then given access for about 2 weeks to the same diet enriched with 5% flaxseed oil in order to restore a sufficient ω3 fatty acid content of tissue lipids. Control rats were exposed for 7 months to a 5% soybean oil-containing diet and then given access for about 2 weeks to the same diet enriched with either 5% flaxseed oil or another 5% soybean oil. In all cases, the increase in the lipid content of the diet provoked an increase in liver triglyceride content. The ratio between the daily increment in the C18:3ω3 content of liver triglycerides caused by the switch in diet and the C18:3ω3 relative content of the diet used after the switch averaged 0.035 in the control rats eventually exposed to the soybean-enriched diet, 0.051 in the control rats eventually exposed to the flaxseed oil-enriched diet and 0.120 in the ω3-deficient rats eventually also exposed to a flaxseed oil-enriched diet. Thus, under the present experimental conditions, the induction or aggravation of liver steatosis, and possibly also the parallel increase in adipose tissue mass, may correspond to the deposition of dietary lipids, also involving an increase in food intake, more pronounced in the ω3-depleted rats than in the control animals.

Keywords:

Long-chain polyunsaturated ω3 fatty acid-depleted rats, soya, sunflower and flaxseed oils, liver phospholipid, triglyceride fatty acid pattern.