Our data indicate that feeding of male Wistar rats with a high carbohydrate normocaloric diet results in a substantial development of obesity. Moreover, exposure of juvenile individuals to obesogenic environment leads, after a certain "latent period", to the development of obesity that may reflect low protein content of used liquid diet or higher resistance of juvenile organism to the obesogenic factors. Finally, based on the data obtained we suggest that Fresubin, with respect to its properties, may serve as a diet for the development of obesity which may exemplify an "obesity model" applicable in small laboratory animals.
We have previously described the development of substantial, but reversible obesity in Wistar rats fed with palatable liquid nutrition (Fresubin). In this study, we investigated changes in serum hormone levels, glycemia, fat mass, adipocyte size, and gene expression of adipokines and inflammatory markers in adipose tissue of Wistar rats fed by Fresubin (i) for 5 months, (ii) up to 90 days of age, or (iii) after 90 days of age to characterize metabolic alterations and their reversibility in rats fed with Fresubin. An intra-peritoneal glucose tolerance test was also performed to determine levels of serum leptin, adiponectin, insulin, and C-peptide in 2- and 4-month-old animals. In addition, mesenteric and epididymal adipose tissue weight, adipocyte diameter, and gene expression of pro- and anti-inflammatory adipokines and other markers were determined at the end of the study. Chronic Fresubin intake significantly increased adipocyte diameter, reduced glucose tolerance, and increased serum leptin, adiponectin, insulin, and C-peptide levels. Moreover, gene expression of leptin, adiponectin, CD68, and nuclear factor kappa B was significantly increased in mesenteric adipose tissue of Fresubin fed rats. Monocyte chemotactic protein 1 messenger RNA (mRNA) levels increased in mesenteric adipose tissue only in the group fed Fresubin during the entire experiment. In epididymal adipose tissue, fatty acid binding protein 4 mRNA levels were significantly increased in rats fed by Fresubin during adulthood. In conclusion, chronic Fresubin intake induced complex metabolic alterations in Wistar rats characteristic of metabolic syndrome. However, transition of rats from Fresubin to standard diet reversed these alterations.
The renin-angiotensin system (RAS) plays an important role in the development of hypertension and has serious consequences on behaviour. The aim of our study was to investigate the effect of hypertension, induced by up-regulated RAS, on the exploration, anxiety-related behaviour and object recognition in laboratory rats. In the experiment, 12 weeks old normotensive Sprague-Dawley (SD) and hypertensive TGR(mREN2)27 (TGR) male rats with up-regulated RAS were used. In the open-field test, the TGR rats were less active in ambulating, rearing and sniffing and more active in self-grooming and urinating than SD ones. In the elevated plus-maze test, the TGR rats showed lower frequency of total arm entries, closed arm entries and higher frequency of defecation than in controls. In the emergence test, TGR rats did not show significant differences. In the novel object recognition task, the TGR rats spent less time with exploration of both familiar and unfamiliar objects but preferred the novel object over the familiar one and exhibited higher percentage of the total exploring time spent with novel object exploration than SD rats. Our results indicate that the TGR rats are less actively exploring, show some modifications of emotional/anxiety-related behavior and exhibited better recognition abilities.
OBJECTIVES: To demonstrate histopathological changes in diabetic kidneys of the rat on ultrastructural level with focusing on glomerular cellular environment. METHODS: Male Wistar rats were administered streptozotocin and after 8 weeks, their kidneys were studied using qualitative transmission electron microscope analysis. RESULTS: In diabetic kidneys, the presence of irregularly thickened glomerular membrana basalis (GBM), often up to six times as compared to healthy kidney GBM, mainly around peripheral capillary loops, was striking. We also demonstrated lamination and split appearance of GBM, with presence of delicate fi brillar structure, which was absent within normal GBM. Accumulation of mesangial matrix was found only occasionally. CONCLUSION: Model may be useful to better understand the mechanisms that play role in the progression of DM-induced renal disease and to comprehend the morphological changes, which this process leaves within the tissue. The clear association between ultra-structure and functional markers may not be necessary (Fig. 4, Ref. 27). Text in PDF www.elis.sk.
Abstract.We determined the effect of chronic liquid nutrition (Fresubin) intake in different developmental stages on the cardiovascular and renal system of male Wistar rats. Body weight, water intake and blood pressure were periodically measured. Selected serum and urine biochemical parameters reflecting metabolic and homeostatic changes after Fresubin intake were investigated as well. Heart and kidney weight, diameter of cardiomyocytes, diameter and length of cardiomyocyte nuclei, wall thickness of thoracic aorta, the diameter and the area of renal corpuscles and serum and urine biochemical parameters were assessed at the end of experiment. We showed that Fresubin intake differently affects the investigated morphological and biochemical parameters in rats and this effect was dependent on the developmental stage when Fresubin was provided. Importantly, we have shown that Fresubin-induced elevation of blood pressure is a reversible phenomenon and it is independent of weight gain and subsequent development of obesity.
Experimental and clinical studies have shown alterations in activity of systems responsible for neuroendocrine stress response in obese individuals. therefore we investigated the effect of palatable normocaloric liquid nutrition (fresubin) on alterations in activity of the hypothalamic-pituitary-adrenal (HPa) axis in male Wistar rats of different developmental stages. control rats (con) received standard pellet chow all the time from weaning (21 st day of age) to 150 days. fresubin was administered throughout the experiment (ln), only in juvenility (from 21 st to 90 th day of age; lnJ) or only in adulthood (from 90 th to 150 th day of age; lna). body weight and energy intake were periodically monitored. adrenal gland and fat tissue weight and plasma corticosterone levels (CORT) was determined after sacrification. Fresubin intake induced obesity in ln and lna rats. in ln and lna rats were observed elevated serum cort levels, but only in LN rats with significant twofold increase compared to LNJ rats. However, the weight of adrenal glands did not differ between ln, lnJ and lna experimental groups. based on our results, we suggest, that obesity induced by fresubin in ln and lna rats is accompanied by increased HPa activity represented by elevated plasma cort levels in these rats.
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