This study was aimed at establishing the effect of total 3-day starvation and that of 28-day food restriction (7-8g standard pellet food daily) on zinc levels in plasma and selected tissues of female Wistar rats. Zinc levels were determined in plasma, red blood cells, liver, and bones. The 3-day starvation led to a statistically significant decrease in plasma, hepatic, and tibia zinc levels in comparison with the respective levels in control animals fed standard pellet food ad libitum. The zinc concentration was also decreased in the liver and bones of rats fed the restricted diet, but they showed unaltered plasma values. No significant change in erythrocyte zinc was observed in either experimental group. The study demonstrated that the 3-day starvation and more prolonged undernutrition exerted marked effects on the organ distribution of zinc. In fast and undernutrition a regulatory system could be supposed that sustains the zinc distribution, according to the tissue priorities.
The influence of intragastric corn peptide (CP) administration on plasma amino acid concentrations and alcohol metabolism was investigated in stroke-prone spontaneously hypertensive rats that were given CP and ethanol intragastrically through a gastric tube or CP alone intragastrically at a dose of 1.0g/kg. CP administered with ethanol significantly elevated the plasma free amino acid concentrations, especially those of alanine, leucine, and proline; and these concentrations reached their maximum at 30min after CP intake. Furthermore, a significant reduction in the increase in blood ethanol concentration was observed. CP administered alone also elevated the concentrations of the same amino acids, and these reached their maximum level at 90min after CP intake when ethanol was given intraperitoneally. In this case, the reduction in the increase in blood ethanol concentration was not observed. Accordingly, these results suggest that CP is effectively absorbed into the system through the intestinal tract in coexistence with ethanol and the elevation in plasma amino acids, alanine, leucine, and proline levels may prevent the increase in blood ethanol concentration after ethanol intake due to the enhancement of alcohol metabolism.
We investigated the effects of an enterally administered lipid emulsion diet containing medium- and long-chain triglycerides (MCT/LCT) on liver function and liver lipid accumulation in septic male Wistar rats suffering from peritonitis. Sepsis was induced by cecal ligation and puncture. One group was fed a fat-free (0%) diet, and the other groups were fed MCT/LCT or LCT as 10% of the total energy. The diets also contained casein oligopeptide, dextrin, vitamins, and trace elements (100kcal/100ml). Enteral feeding was ended on the 6th day. Liver dysfunction was observed in the fat-free diet group; both serum glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities were about 3 or more times higher than those in the two fat-fed groups, in which no significant elevation in enzyme activities was observed. The absolute liver weight and the accumulation of liver lipid were significantly higher in the fat-free diet group than in the MCT/LCT and LCT diet groups, and no significant differences in these variables were observed between the latter two groups. The level of serum non-esterified fatty acids (NEFA), which are an energy source in the peripheral tissue, was higher in the MCT/LCT group than in the LCT group, but there was no significant difference between the groups for serum triglycerides. These results indicate that MCT/LCT as 10% of the total energy has the same effect on liver function and lipid accumulation in septic rats as an LCT diet and prevents from enhancement of liver lipid accumulation.
The phospholipid fatty acid composition of three parts of gastrointestinal tract (GIT) possessing different functions (stomach, jejunum, and colon) was examined to determine if these gut segments consistently respond to dietary fat. Three groups of eight weanling male Sprague-Dawley rats were fed one of three isocaloric, semi-synthetic, nutritionally adequate diets for six weeks. The fat type in the control diet was primarily beef tallow supplemented with sufficient linoleic acid (18: 2n-6) to prevent essential fatty acid deficiency, the n-6 diet contained high levels of 18:2n-6, and the n-3 diet provided high levels of eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) acids with similar levels of 18:2n-6 as in the control diet. Feeding the n-3 diet resulted in the incorporation of 20:5n-3 and 22:6n-3 into all the GIT segments examined; however, the incorporation was significantly higher in the jejunum and the colon, compared with that in the stomach, phospholipids. The arachidonic acid (20:4n-6) content was lower in the stomach, jejunum, and colon phospholipids following the feeding of the n-3 diet. The 18: 2n-6 content was found to be higher following consumption of the n-3 diet compared with that found for the control diet. The 20:4n-6 content was significantly higher in the jejunum than in the colon or stomach phospholipids, whereas the 18:2n-6 content was consistently higher in all the GIT segments in animals fed the n-6 diet. This diet group also exhibited lower levels of monounsaturated fatty acids in the stomach and lower levels of saturated fatty acids in the jejunum and the colon phospholipids. Thus, dietary fat manipulations inconsistently influence the phospholipid fatty acid composition of various parts of the GIT, suggesting that the functioning of the stomach, jejunum, and colon may be affected differently by alterations in the type of dietary fat ingested.
The effect of administration of thioacetamide on rat liver mitochondrial functions and the protective effect of an aqueous extract of Phyllanthus fraternus against thioacetamide-induced damage were studied. When rats were treated with thioacetamide, the rate of mitochondrial respiration was decreased significantly with both NAD+ linked and FAD linked substrates, and the respiratory control ratio, an index of membrane integrity and the P/O ratio, a measure of phosphorylation efficiency, decreased significantly. Also, there was a significant decrease in the activities of NADH dehydrogenase, succinate cytochrome c reductase, and cytochrome oxidase; whereas succinate dehydrogenase was not affected. A significant decrease was seen in membrane potential and in the level of mitochondrial ATP. There was a significant decrease in the levels of phosphatidylcholine, phosphatidylethanolamine, and cardiolipin by thioacetamide treatment. The lipid peroxide level increased significantly in thioacetamide-treated rats. Administration of P. fraternus prior to thioacetamide treatment relieved the inhibition of all the parameters studied, and brought down the lipid peroxide levels significantly in liver homogenates and mitochondria. This study shows that P. fraternus protects against thioacetamide-induced toxicity by its ability to suppress the elevated lipid peroxide levels in the mitochondrial membrane.
Lung fibrosis was induced in rats by exposing them to fractionated irradiation, bleomycin instillation into the lung, or paraquat treatment. Lung lipid peroxides, serum lipid peroxides, and lung collagen hydroxyproline were found to be significantly elevated (>100%) in rats after exposure to these agents over a period ranging from 25 days to 60 days. Antioxidants curcumin, ellagic acid, bixin, and α-tocopherol reduced significantly the serum and lung lipid peroxides. Consequent to the decrease in peroxides, lung collagen hydroxyproline was reduced to almost the normal level in these animals. These results indicate the usefulness of the above non-toxic antioxidants in conditions of lung fibrosis produced by various xenobiotic agents.
Lipid peroxidation and inflammatory response were studied in smokers and non-smokers after myocardial infarction (MI). The MI group studied included 18 smokers and 15 non-smokers, and 20 smokers without vascular complications served as controls. The results obtained showed that in both smokers and non-smokers the onset of MI brought about a reduction (p<0.001) in the erythrocyte antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, and catalase) and antioxidant scavenger levels (vitamins A, C, and E and reduced glutathione). Lipid peroxide level measured in terms of thiobarbituric acid-reactive substances increased by several fold (p<0.001). Levels of proinflammatory cytokines (interleukin-1β, interleukin-6, and tumor necrosis factor-α) and acute-phase proteins (plasma-acid glycoprotein, 2-macroglobulin, C-reactive protein, and ceruloplasmin) were also increased by several fold (p<0.001). Though alterations were observed in smokers as well as non-smokers after an episode of MI the percentage of alterations observed was higher in the smokers. This may be due to the smoking-induced free radical production in the presence of decreased antioxidant status, which, in turn, enhances lipid peroxidation and inflammatory responses. Hence, the data suggest that smokers may benefit from oral supplementation with antioxidant vitamins to alleviate smoking-induced free radical damage and inflammatory responses.