Indicators of vitamins safety in experimental alimentary
hyperlipidemia in rodents
Rats and mice of different strains are used as a model of metabolic disturbances, caused by the consumption of diets with unbalanced content of macro-nutrients (fat, carbohydrate), as well as having elevated cholesterol quota. The aim of this study was to determine the magnitude and direction in change of vitamins status indices produced in rats and mice with experimental-mental hyperlipidemia, developing under consumption of high fat diet (HFD), fructose (Fr) and cholesterol (Cho). The experiment was conducted on 48 female growing Wistar rats with initial body weight 122 ±12 g, and 48 female growing C57Black/6 mice with initial body weight 18±1 g, which were divided into 12 groups of 8 animals per group. Within 63 days the rats and mice of the first (control) group received a balanced semi-synthetic (BD), 2nd groups - HFD with 30% of the total fat by weight of dry feed, 3rd groups - BD and Fr solution instead of water, 4th groups - HFD+Fr, 5th groups - BD supplemented with 0.5% Cho by weight of dry food, 6th groups - the same ration and Fr. After removal of animals from the experiment there were determined the content of vitamin A (retinol and retinol palmitate) and E (α-tocopherol) in blood plasma and liver by HPLC, 25-hydroxycholecalciferol [25(OH)D] in blood plasma by HPLC-MS, vitamins B1, B2 and oxidized NAD coenzymes in liver by fluorimetric methods. Consumption of HFD resulted in marked increase in the concentration of vitamin A by 32% and by 45% in rat blood plasma and in the mice liver respectively, elevation of vitamin E level by 46% in the rat liver. Unlike rats, vitamin E in the liver of mice treated with HFD was lower by 32% compared with the control. Cho additive resulted in increased vitamin E accumulation in rat and mice liver (α-tocopherol level was 2.5 и 1.5 fold higher than in control respectively). Convincing evidence wasn't revealed of the impact of the additional Fr on vitamins A and E safety in rats and mice. Consumption of Fr on background of HFD in rats significantly reduced the level of 25(OH)D compared with HFD without Fr. Fr reception in combination with the addition of Cho significantly reduced stores of vitamin A and increased - of vitamin E in the liver of rats and mice. 25(OH)D level for this type of diet was significantly reduced. Cho consumption in rats significantly decreased the content of NAD+NADP in the liver by 12%; the introduction of fructose into the diet neutralized this impact. Feeding rats with HFD resulted in a significant improvement, and uptake of Cho in reduce of vitamin B2 levels in the liver by 12.8 and 28%, respectively. Fr partially neutralized these effects. Thus, changes in the ratio of macronutrients and Cho in the diet of rats and mice may lead to a partially species-specific vitamin sufficiency variations, including in some cases the development of functional deficiency of vitamins А, B2, D and NAD coenzymes.
Keywords:hyperlipidemia, in vivo model, rats, mice, fructose, cholesterol, vitamin A, vitamin E, vitamin D, water-soluble vitamins
Voprosy pitaniia [Problems of Nutrition]. 2017; 86 (1): 6-16. doi: 10.24411/0042-8833-2017-00015.