Effects of Tyrosine and Tryptophan Supplements on the Vital Indicators in Mice Differently Prone to Diet-Induced Obesity

We studied the effects of the addition of large neutral amino acids, such as tyrosine (Tyr) and tryptophan (Trp), in mice DBA/2J and tetrahybrid mice DBCB receiving a high-fat, high-carbohydrate diet (HFCD) for 65 days. The locomotor activity, anxiety, muscle tone, mass of internal organs, liver morphology, adipokines, cytokines, and biochemical indices of animals were assessed. The Tyr supplementation potentiated increased anxiety in EPM and contributed to a muscle tone increase, a decrease in the AST/ALT ratio, and an increase in protein anabolism in both mice strains. Tyr contributed to a decrease in liver fatty degeneration and ALT reduction only in DBCB that were sensitive to the development of obesity. The addition of Trp caused an increase in muscle tone and potentiated an increase in anxiety with age in animals of both genotypes. Trp had toxic effects on the livers of mice, which was manifested in increased fatty degeneration in DBCB, edema, and the appearance of micronuclei in DBA/2J. The main identified effects of Tyr on mice are considered in the light of its modulating effect on the dopamine neurotransmitter metabolism, while for the Trp supplement, effects were presumably associated with the synthesis of its toxic metabolites by representatives of the intestinal microflora.

Effect of resveratrol on behavioral, biochemical, and immunological parameters of DBA/2J and tetrahybrid DBCB mice receiving diet with excess fat and fructose

Polyphenolic biologically active substances (BAS) including resveratrol (R) can exert beneficial effects on fat accumulation, blood pressure, glycemia, insulin sensitivity, and plasma lipid profile in patients with obesity, and associated diseases. The study aimed to determine the effect of R at a dose of 25 mg/kg body weight on the DBA/2J and DBCB mice with diet-induced obesity followed by the consumption high-fat high-carbohydrate diet (HFCD). Behavioral reactions (elevated plus maze [EPM]) and muscle tone (the strength of the forepaw grip) were tested, and plasma biochemical and immunological parameters were assessed. In the repeated EPM test, anxiety increased only in DBCB mice during the second trial. In DBCB mice treated with HFCD, the muscle tone decreased with the second trial; however, this effect was not observed in the background of R consumption. R decreased the level of triglycerides, diminished the activities of alanine and asparagine aminotransferases, which were elevated upon HFCD consumption. Ghrelin level increased after R consumption in mice of both genotypes. The leptin to ghrelin ratio was reduced in DBCB mice receiving R. Consumption of R increased IL-3 and IL-10 levels in both DBA/2J and DBCB mice. IL-12p70 level increased in DBCB mice in response to R. R addition to HFCD reduced several symptoms of dyslipidemia in highly sensitive tetrahybrid mice. The results obtained indicate the importance of a personalized (depending on the genotype) approach when any R prescription, among other BAS and dietary factors, are used in diet therapy for patients with low, moderate and high-risk obesity.

[Effect of quercetin on the expression of the carbohydrate and lipid metabolism genes in the liver of rats with genetic]

Quercetin (Q; 3,3',4',5,7-pentahydroxyflavone) is considered as a promising component of specialized products for the correction of metabolic disorders in obesity and metabolic syndrome. At the same time, the results of evaluating the clinical efficacy of Q are ambiguous, and the mechanisms of its influence on lipid and carbohydrate-energy metabolism are not well understood. The aim of the work was to study the effect of quercetin (Q 3,3',4',5,7-pentahydroxyflavone) on the expression of key glycolysis and lipogenesis enzymes' genes in Zucker-Leprfa (Z) rats characterized by hereditary obesity, compared to «wild-type» Wistar (W) rats. Material and methods. 24 male Z rats and 32 male W rats aged 8-10 weeks were used. Animals of each line were divided into 4 groups of equal numbers. For 62 days the animals of the first groups (controls) received a balanced diet according to AIN93M, the seconds - the same diet with Q added in a dose of 50 mg/kg body weight. Animals of the third groups received a high-fat, high-carbohydrate diet (HFCD) with fat 30% by weight and with the replacement of drinking water with a 20% solution of fructose, the fourths groups - the same diet and supplementation with Q. After removing animals from the experiment, expression levels of liver carbohydrate and lipid metabolism genes Khk, Gck, Pklr, Acaca, Fasn, Scd, Srebf1, Mlxipl, Ppara and Pparg were determined by real-time polymerase chain reaction (RT-PCR) with reverse transcription using Actb and Gapdh as reference genes. The levels of triglycerides, total and HDL cholesterol, lipolytic activity and immunoreactive leptin were determined in plasma. Results and discussion. When comparing two animal lines, a significantly higher level of expression of Ppara, Pparg, Mlxipl, Acaca, Fasn, Scd was shown in Z rats compared to W rats, which is consistent with the development of dyslipidemia in the first ones and elevated levels of leptin under both types of diets used. The addition of Q caused in W rats a decrease in the expression of Scd, Mlxipl, Khk and Gck, more pronounced on the background of HFCD whereas in Z rats there were no similar effects, or they had the opposite direction. In addition, in Z rats, consumption of Q led to increased expression of Pklr, which was not observed in W rats. Conclusion. The modulating effect of Q on the expression of key genes of lipid and carbohydrate metabolism enzymes significantly differs in wild-type W rats and mutant Z rats with hereditary obesity, and this difference appears to be potentiated by the consumption of excess fat and fructose.

Comparative analysis of the influence of a high-fat/high-carbohydrate diet on the level of anxiety and neuromotor and cognitive functions in Wistar and DAT-KO rats

We compared anxiety, neuromotor, and cognitive functions in mutant rats with different allelic variants of dopamine transporter DAT knockout receiving balanced or excess in fat and fructose diet. The experiments were performed in DAT-/- homozygotes, DAT+/- heterozygotes, and DAT+/+ wild type rats. The genotype of DAT-KO rats was confirmed by restriction analysis of DAT gene compared to behavioral responses in the open field test (OF). Animals in the first groups of each strain were fed a balanced AIN93M diet; and those in the second groups with a high-fat/high-fructose diet. Neuromotor function was studied as grip strength, and behavioral responses were assessed in the elevated plus maze and conditioned passive avoidance response tests. The mass of the internal organs and white and brown fat, as well as selected lipid and nitrogen metabolism parameters in blood plasma were determined at the end of the experiment. DAT-/- had the highest specific grip strength, and showed an increase in initial exploratory activity in comparison with DAT+/- and DAT +/+. The exploratory activity was significantly reduced in the second test compared to the first one in DAT-/- and DAT+/- of first but not second group. Anxiety decreased with age in the second groups of DAT+/- and DAT+/+ (but not in DAT-/-) and was higher in DAT+/+ than in DAT+/- and DAT-/-. Excess fat and fructose resulted in the deterioration of short-term memory in DAT+/+. Lipidomic indices of blood plasma were less responsive to diet in DAT-/- and DAT-/+ in comparison to DAT+/+. The increased AsAT/AlAT activity ratio in DAT-/- compared with those in DAT+/+ suggests the activation of catabolism activity in the mutants. The consumption of excess fat and fructose significantly modified the effects produced by DAT gene allelic variants presumably due to the influence on the processes of dopamine metabolism.

[Effect of B-vitamin deficiency on biochemical, immunologic markers and trace element status of rats and mice of various lines]

Biochemical, vitamin, trace element and immunological changes were searched for the combined nutritional deficiency of vitamins B1, B2, B6 on in vivo models in rats and mice. Female rats of Wistar (W) strain and hybrids of the 1st generation of Dark Aguti and Wistar (DA x W) strains, female mice of BALB/c strain and DBCB tetrahybrids were used in experiment. Animals received for 35 days a balanced diet (control) according to AIN-93 or a similar diet with the exception of vitamins B1, B2, B6 (experimental groups). The content of vitamins B1, B2 in liver, riboflavin blood plasma level and urinary excretion of thiamine, riboflavin and 4-pyridoxic acid were determined, as well as in rats: blood and liver content of α-tocopherol and retinol, blood biochemical indices of lipid and nitrogen metabolism, activity of cytochrome P isoforms-450 (CYP) in liver; in mice: the circulating levels of pro- and anti-inflammatory cytokines of blood plasma, in animals of both species - the content of essential and toxic elements in the kidneys. DAxW rats compared to W and DBCB mice compared to BALB/c were more sensitive to the development of B-vitamin deficiency judging by the B-vitamin status indicators. In the rats of the experimental groups, there were signs of a deterioration in blood and liver levels of vitamin E, multidirectional shifts in vitamin A sufficiency, increased activity of the CYP3A isoform (6β-TG), a decrease in triglycerides, total protein and albumin fraction levels with an increase in urea level. Manifestation degree of these effects depended on the choice of the animal's line. In mice, the B-vitamin deficiency was characterized by an increase in the levels of proinflammatory cytokines TNF-α, IL-10, IL-Ιβ, IL-6 and a decrease in IFN-γ and IL-17A. The content of magnesium, copper, zinc, chromium and silver was lowered, of cesium - was increased in the kidneys of the rats of the experimental groups. In mice, B-vitamin deficiency resulted in diminishment of magnesium, copper, zinc, chromium, selenium, cadmium and lead content, excess accumulation of cobalt and cesium. Some of these biomarkers are supposed to be used in pre-clinical evaluation of the effectiveness of new vitamin complexes, specialized foods and dietary supplements, as well as studies of interactions of various vitamins.

[Comparative characteristics of in vivo models of hyperlipidemia in Wistar rats and C57Bl/6 mice]

In vivo simulation of lipid disorders (hyperlipidemia, obesity, metabolic syndrome, atherosclerosis) is of considerable interest to search for genomic, transcriptomic and metabolomic markers that allow for differential diagnosis, prognosis and selection of personalized diet therapy in patients with such pathology. The aim of the study was the development and characterization of basic biochemical parameters of in vivo models of alimentary hyperlipidemia in outbred rats and inbred mice. The experiment was con­ducted on 48 growing female Wistar rats, and 48 growing female mice of line C57Black/6, which were divided into 12 groups of 8 animals per group. Within 63 days the rats and mice of first (control) group received a balanced semi synthetic diet (BD), the animals of the second groups - high-fat diet (HFD) with 30% of the total fat by weight of dry feed, third groups - BD and fructose solution (Fr) instead of water, the fourth groups -HFD + Fr, fifth groups - BD supplemented with 0.5% cholesterol (Cho) by weight of dry feed, sixth groups - BD with Cho and Fr. The amount and composition of diets consumed were corrected during the experiment for their closest approach in calories. After removal of animals from the experiment there were determined the mass of internal organs, HDL, LDL, total cholesterol, triglycerides, glucose in blood plasma, total lipids and their fatty acid composition in liver, ghrelin, GIP, GLP-1, glucagon, leptin, PAI-1, resistin levels in blood plasma. It was found that in both species the liver is the most sensitive to nutritional imbalance, nutrient exerting the greatest impact on this was Fr. In rats, as compared to mice, there was significantly more pronounced shifts in lipoprotein spectrum in response to nutritional imbalances, especially to the consumption of additional Cho, which was manifested in an increase of LDL, decrease of HDL and magnification of atherogenic index. In the liver of rats fed diets with Cho, marked steatosis developed manifested in a disproportionate increase in the lipid content and accompanied by changes in their fatty acid composition, especially in the ratio ω6 to ω3 PUFAs. Changing of hormones - regula­tors of carbohydrate metabolism (GLP, glucagon) and ghrelin was significantly greater in mice than in rats as a result of consumption of additional Fr. Effect had the opposite direction in two species of Cho and Fr combining on leptin levels. The significance is dis­cussed of the revealed interspecies differences in the light of the characteristics of lipid and glucose metabolism in these two lines of animals that are the most common models of alimentary-dependent diseases.