The metabolic syndrome of ω3-depleted rats. I. Liver data

Abstract

Abstract. Second-generation rats depleted in long-chain polyunsaturated ˆ3 fatty acids were recently proposed as a novel animal model for the metabolic syndrome. In the present study, a dietary deprivation of ˆ3 acids for 3-7 months was found sufficient to provoke in 6-week-old normal rats the same alteration of the fatty acid content and profile of liver phospholipids and triglycerides as that otherwise prevailing in the second-generation ˆ3-depleted rats, with emphasis on a severe decrease in their ˆ3 fatty acid content, alterations in the relative contribution of and ratio between selected long-chain polyunsaturated ˆ6 fatty acids, saturated and monodesaturated fatty acids and precursors of nervonic acid, and liver steatosis. When the ˆ3-depleted rats were exposed, after the first 7 months of the present experiments and for 2-4 weeks to a diet supplemented with 5% (w/w) flaxseed oil, most of these hepatic variables returned towards or beyond control values. In both the ˆ3-depleted rats and control animals, however, the eventual exposure to the flaxseed oilenriched diet failed to suppress liver steatosis and, on the contrary, provoked a further increase in liver triglyceride content. It is proposed, therefore, that the present approach represents a simple and realistic animal model to study the consequences of ˆ3-depletion. Moreover, the results suggest that to oppose such consequences, e.g. liver steatosis, it may be necessary to combine the dietary supply of ˆ3 acids with a suitable control of food intake, in both qualitative and quantitative terms.

The metabolic syndrome of ω3-depleted rats. IV. Intestinal phospholipid ω3 fatty acids

“…The 8 groups of 5-6 female rats each were the same as those indicated in our first report in this series (1). Briefly, 4 of these groups included control rats exposed for 3 or 7 months to a diet containing 5% (wt/wt) soybean oil and then given access for 4-5 weeks to the same diet enriched with either another 5% of soybean oil or 5% of flaxseed oil.…”

“…The other 4 groups consisted of rats exposed for 3 or 7 months to a diet containing 5% sunflower oil and then given access for 2 or 4-5 weeks to the same diet enriched with 5% flaxseed oil. The fatty acid composition of these diets and the modalities of sacrifice and tissue sampling were also described in our prior publication (1). The small and large bowel segments were removed from mesenteric and vascular connections and sequentially removed from the peritoneum.…”

“…In the first 3 reports in this series, it was documented that a dietary deprivation of long-chain polyunsaturated ˆ3 fatty acids initiated in 7-week-old normal rats was sufficient within 3 to 7 months to reproduce several features of the metabolic syndrome, including liver steatosis, visceral obesity and insulin resistance, as otherwise found in second-generation rats depleted in these ˆ3 fatty acids (ˆ3D rats) (1)(2)(3). The time course for the repletion of ˆ3 fatty acids in liver and brain was also investigated when the ˆ3D rats were given access for 2 to 4-5 weeks to a flaxseed oil-enriched diet.…”

The metabolic syndrome of ω3-depleted rats. V. Intestinal phospholipid ω6 fatty acids

“…The 8 groups of 5-6 female rats each were the same as those indicated in our first report in this series (2). Briefly, 4 of these groups included control rats exposed for 3 or 7 months to a diet containing 5% (wt/wt) soybean oil and then given access for 4-5 weeks to the same diet enriched with either another 5% of soybean oil or 5% of flaxseed oil.…”

“…The other 4 groups consisted of rats exposed for 3 or 7 months to a diet containing 5% sunflower oil and then given access for 2 or 4-5 weeks to the same diet enriched with 5% flaxseed oil. The fatty acid composition of these diets and the modalities of sacrifice and tissue sampling were also described in our prior publication (2). The small and large bowel segments were removed from mesenteric and vascular connections and sequentially removed from the peritoneum.…”