Beneficial effects of polyunsaturated fatty acids in partially nephrectomized rats

Evening primrose oil, safflower oil, and salmon oil, all with high polyunsaturated fatty acid content, were fed to partially nephrectomized rats; the effects were compared to those of feeding beef tallow. All three oils had favorable effects on progression of renal failure, salmon oil on kidney histology as well. The changes induced in platelet production of thromboxane A2, and in the renal production of various eicosanoids may explain the protective role of these oils.     

Beneficial effects of polyunsaturated fatty acids in partially nephrectomized rats

Evening primrose oil, safflower oil, and salmon oil, all with high polyunsaturated fatty acid content, were fed to partially nephrectomized rats; the effects were compared to those of feeding beef tallow. All three oils had favorable effects on progression on renal failure, salmon oil on kidney histology as well. The changes induced in platelet production of thromboxane A₂, and in the renal production of various eicosanoids may explain the protective role of these oils.     

Dietary fatty acids effects on sucrose-induced cardiovascular syndrome in rats

Cardiovascular disease is one of the leading causes of morbidity and mortality in Mexico. We investigated the effects of omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids on the metabolic syndrome associated with cardiovascular disease in a high-sucrose-fed rat model. The metabolic syndrome-induced rats showed a significant increase in systolic blood pressure, serum insulin, nonfasting serum triglyceride and serum cholesterol levels. Experimental high-sucrose-fed animals received either a n-3 or n-6 enriched diet or a control diet during 6 weeks. Animals fed the n-3 enriched diet had a significant reduction in blood pressure and serum insulin and triglyceride levels. Serum triglyceride levels were also significantly reduced in the n-6-rich diet animals.     

The effects of nutritional polyunsaturated fatty acids on locomotor activity in spontaneously hypertensive rats

The present study investigated the effects of nutritional omega-3 polyunsaturated fatty acids on locomotor activity in spontaneously hypertensive rats (SHRs), which are used as an animal model of attention-deficit/hyperactivity disorder (ADHD). For 6 weeks, two groups of randomly assigned SHRs received food either enriched with or deficient in omega-3 fatty acids (based on the American Institute of Nutrition—93 G/AIN93G). Using an open field, locomotor activity was subsequently assessed for 6 days. A marked difference in locomotor activity as assessed by the distance travelled in the open field was found between the two groups of rats. In comparison with rats fed with omega-3 fatty acid-enriched food, the animals on the omega-3 fatty acid-deficient diet showed a significantly higher locomotor activity. The present findings demonstrated that nutritional enrichment with omega-3 fatty acids was associated with reduced motor activity in an established animal model of ADHD and support the notion that omega-3 polyunsaturated fatty acids may play a role in the pathophysiology of ADHD.     

Metabolism and effects on cholestasis of isoursodeoxycholic and ursodeoxycholic acids in bile duct ligated rats

Isoursodeoxycholic acid (isoUDCA), the 3 beta-epimer of ursodeoxycholic acid (UDCA), may have pharmaceutical potential because of its similar hydrophilicity and in vitro cytoprotection as compared with UDCA. We compared metabolism and effects on cholestasis of UDCA and isoUDCA in experimental cholestasis in rats. Cholestasis was induced by bile duct ligation. For bile flow and biliary bile acid analysis, UDCA or isoUDCA were infused intraduodenally. For the study of chronic effects, chow was supplemented with 2.5 g/kg UDCA or isoUDCA for 3 weeks. Sham-operated animals served as controls. IsoUDCA became completely converted to UDCA in the liver. Choleresis and biliary bile acids were the same after the intraduodenal administration of either compound. Oral administration of UDCA or isoUDCA significantly improved liver biochemistry but not clinical and histological parameters in chronic cholestasis. The decrease of serum cholic acid in control animals was more pronounced after isoUDCA (-93%) than after UDCA (-76%). Only after UDCA, this decrease was compensated by increases of UDCA, beta-muricholic acid (MCA), and Delta(22)-beta-MCA. Our results show that isoUDCA has the same effect on choleresis and liver biochemistry as UDCA. IsoUDCA features pro-drug characteristics of UDCA and causes compared to the latter lower serum bile acid concentrations in non-cholestatic animals.     

Acute effects of caffeine injection on neutral amino acids and brain monoamine levels in rats

The injection of caffeine (100 mg/kg, i.p.) into male rats acutely increased brain levels of trytophan, serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA). Blood levels of glucose, nonesterified fatty acids (NEFA) and insulin also increased, while those of the aromatic and branched-chain amino acids fell. Serum tryptophan levels either did not fall, or increased. Consequently, the serum ratio of trypthopahn to the sum of other large neutral amino acids (LNAA) increased. Less consistently noted were increases in serum free tryptophan levels. Brain tyrosine levels were not appreciably altered by caffeine, nor was the serum tyrosine ratio. In dose-response studies, 25 mg/kg of caffeine was the minimal effective dose needed to raise brain tryptophan, but only the 100 mg/kg dose elevated all three indoles in brain. In no experiments did caffeine, at any time or dose, alter brain levels of dopamine or norepinephrine. Caffeine thus probably raises brain tryptophan levels by causing insulin secretion, and thereby changing plasma amino acid levels to favor increased tryptophan uptake into brain. The rises in brain 5-HT and 5-HIAA may follow from the increase in brain tryptophan, although further data are required clearly to establish such a mechanism.     

Metabolism of amino acids in protein-calorie-deficient rats

The overall oxidative degradation of leucine and phenylalanine, measured in vivo in rats fed on a 2%-casein diet for 8 weeks, is markedly decreased as compared with controls, whereas that of glutamate and alanine is apparently unaffected. The decrease in leucine degradation is due, at least in part, to a block before the formation of 3-methylbutyryl-CoA (isovaleryl-CoA) in the catabolic pathway. This phenomenon is accompanied by increased incorporation of [¹⁴C]leucine into liver proteins, decreased urinary excretion of leucine and increased urinary excretion of 4-methyl-2-oxopentanoate (α-oxoisocaproate) by protein-depleted animals. The results suggest the existence of adaptive mechanisms that function to conserve an indispensable carbon skeleton.     

Prophylactic and therapeutic effects of Mytilus edulis fatty acids on adjuvant-induced arthritis in male Wistar rats

Lipid-rich fractions from the flesh tissue of Mytilus edulis were obtained by solvent extraction and chromatographic separation, and tested for anti-inflammatory (AI) activity in vitro and in vivo. Inhibition of leukotriene production by isolated human neutrophils in response to calcium ionophore stimulation in the presence of exogenous arachidonic acid substrate was demonstrated for the hydrolysed triglyceride fraction of the crude lipid extract. This fraction was subsequently tested for in vivo AI activity using the mycobacterial adjuvant-induced polyarthritis rat model. The hydrolysed triglyceride fraction showed significant AI activity when dosed therapeutically (10 mg/kg BW/day, p.o., for 6 days from the onset of arthritis), decreasing body weight loss by 55% and hind paw swelling by 65% compared to the arthritic control. The (non-hydrolysed) crude lipid extract was effective when dosed prophylactically (30 mg/kg BW/day, p.o., for 16 days starting on day ?2 of arthritigen inoculation). Structural analysis by GC and GC–MS revealed in the extracts an abundance of EPA (20:5n-3) and DHA (22:6n-3) (37% of total fatty acids), along with a small quantity of a rare anti-inflammatory n-3 analogue of arachidonic acid, namely 7, 11, 14, 17-eicosatetraenoic acid (20:4n-3).     

Protective effects of omega-3 essential fatty acids against formaldehyde-induced neuronal damage in prefrontal cortex of rats

The aim of this study was to examine the neurotoxicity of formaldehyde on prefrontal cortex and the protective effects of omega-3 essential fatty acids against these toxic effects. For this purpose, 21 male Wistar rats were divided into three groups. The rats in group I comprised the controls, while the rats in group II were injected every other day with formaldehyde (FA). The rats in group III received omega-3 fatty acids daily while exposed to formaldehyde. At the end of the 14-day experimental period, all rats were killed by decapitation. The brains of the rats were removed and the prefrontal cortex tissues were obtained from all brain specimens. Some of the prefrontal cortex tissue specimens were used for determination of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels. The remaining prefrontal cortex tissue specimens were used for light microscopic and immunohistochemical evaluation. The levels of SOD and GSH-Px were significantly decreased, and MDA levels were significantly increased in rats treated with formaldehyde compared with those of the controls. Furthermore, in the microscopic examination of this group, formation of apoptotic bodies, pycnotic cells, and apoptotic cells including nuclear fragmentation and membrane budding were observed. However, increased SOD and GSH-Px enzyme activities, and decreased MDA levels were detected in the rats administered omega-3 fatty acids while exposed to formaldehyde. Additionally, cellular damage caused by formaldehyde was decreased, and structural appearance was similar to that of the control rats in this group. The biochemical and histological findings observed in all groups were also confirmed by immunohistochemical evaluation. It was determined that formaldehyde-induced neuronal damage in prefrontal cortex was prevented by administration of omega-3 essential fatty acids.     

Protective effects of polyunsatutared fatty acids supplementation against testicular damage induced by intermittent hypobaric hypoxia in rats

Background

Intermittent hypobaric hypoxia (IHH) induces changes in the redox status and structure in rat testis. These effects may be present in people at high altitudes, such as athletes and miners. Polyunsaturated fatty acids (PUFA) can be effective in counteracting these oxidative modifications due to their antioxidants properties. The aim of the work was to test whether PUFA supplementation attenuates oxidative damage in testis by reinforcing the antioxidant defense system. The animals were divided into four groups (7 rats per group): normobaric normoxia (~750 tor; pO2 156 mmHg; Nx); Nx + PUFA, supplemented with PUFA (DHA: EPA = 3:1; 0.3 g kg⁻¹ of body weight per day); hypoxic hypoxia (~428 tor; pO2 90 mmHg; Hx) and, Hx + PUFA. The hypoxic groups were exposed in 4 cycles to 96 h of HH followed by 96 h of normobaric normoxia for 32 days. Total antioxidant capacity (FRAP) and lipid peroxidation (malondialdehyde, MDA) in plasma and reduced (GSH)/oxidized glutathione (GSSG) ratio, tissue lipid peroxidation (TBARS) and antioxidant enzymes activity were assessed at the end of the study in testis. Also, SIRTUIN 1 and HIF-1 protein expression in testis were determined.

Results

IHH increased lipid peroxidation in plasma and HIF-1 protein levels in testis. In addition, IHH reduced FRAP levels in plasma, antioxidant enzymes activities and SIRTUIN 1 protein levels in testis. PUFA supplementation attenuated these effects, inducing the increases in FRAP, in the antioxidant enzymes activity and HIF-1 levels.

Conclusions

These results suggest that the IHH model induces a prooxidant status in plasma and testis. The molecular protective effect of PUFA may involve the induction of an antioxidant mechanism.     

Differential effects of fatty acids and exercise on body weight regulation and metabolism in female Wistar rats

High-fat diets made with different fats may have distinct effects on body weight regulation and metabolism. In the present study, the metabolic effects of high-fat (HF) diets made with fish oil, palm oil, and soybean oil were compared with a low-fat diet in female Wistar rats that were either exercised (EX, swimming) or that remained sedentary as controls. Each adult rat was exposed to the same diet that their dams consumed during pregnancy and lactation. When they were 9 weeks old, rats began an EX regimen that lasted for 6 weeks. Twenty-four hours after the last EX bout, rats were sacrificed in a fasted state. It was observed that HF feeding of soybean oil induced more body weight and fat gain, as well as insulin resistance, as indicated by insulin/glucose ratios, than other oils. Female rats fed a HF diet made with fish oil had body weight and insulin sensitivity not different from that observed in low fat fed control rats. For rats fed HF diets made with soybean oil or palm oil, EX also exerted beneficial effects by reducing body fat %, blood insulin, triglyceride and leptin levels, as well as improving insulin sensitivity.     

Mobilization of fatty acids in genetically obese rats

The mobilization of fatty acids has been studied in genetically obese rats of the Zucker strain and in control obese animals with bilateral destructive lesions in the hypothalamus. The body weight and size of adipose cells did not differ significantly between the genetically obese rats and the obese controls. Weight loss in control and genetically obese rats was identical during a 1 month fast. The release of glycerol and the rise in free fatty acids in adipose tissue incubated in vitro were similar in tissue from genetic and hypothalamic obese rats. Epinephrine, theophylline, and dibutyryl cyclic adenosine monophosphate all augmented lipolysis, and the effects were usually greater in the tissues from genetically obese rats.     

Gender-related long-term effects in adult rats by perinatal dietary ratio of n-6/n-3 fatty acids

Epidemiological studies in humans have shown that perinatal nutrition affects health later in life. We have previously shown that the ratio of n-6 to n-3 polyunsaturated fatty acids (PUFA) in the maternal diet affects serum leptin levels and growth of the suckling pups. The aim of the present study was to investigate the long-term effects of various ratios of the dietary n-6 and n-3 PUFA during the perinatal period on serum leptin, insulin, and triacylglycerol, as well as body growth in the adult offspring. During late gestation and throughout lactation, rats were fed an isocaloric diet containing 7 wt% fat, either as linseed oil (n-3 diet), soybean oil (n-6/n-3 diet), or sunflower oil (n-6 diet). At 3 wk of age, the n-6/n-3 PUFA ratios in the serum phospholipids of the offspring were 2.5, 8.3, and 17.5, respectively. After weaning, all pups were given a standard chow. At the 28th postnatal wk, mean body weight and fasting insulin levels were significantly increased in the rats fed the n-6/n-3 diet perinatally compared with the other groups. The systolic blood pressure and serum triacylglycerol levels were only increased in adult male rats of the same group. These data suggest that the balance between n-6 and n-3 PUFA during perinatal development affects several metabolic parameters in adulthood, especially in the male animals.     

Biological effects of lipoteichoic acids.

Pneumococcal lipoteichoic acid (Forssman antigen) added to the medium of growing pneumococcal cultures caused chain formation, prevented culture lysis in the stationary phase of growth, and inhibited lysis by penicillin and by the pneumococcal bacteriophage Dp-1.