engleski

Diet induced hepatic steatosis in rat

Introduction New investigations show that liver steatosis associated with high fat diet is one of the commonest liver disease today. So far, it was not clearly established how feeding with high quantity of different kind of fats act on liver and does it produce steatosis. Zato je cilj istraživanja bio ustanoviti kako konzumacija velike količine suncokretovog ulja u prehrani djeluje na jetru štakora. Material and methods Animals and diet In all experiments, male adult Wistar rats weighing 250-325 g were used. Rats were housed individually in wire cages in a temperature-controlled room (21+ 1˚ C) on a 12 – h light-dark cycle, with free access to food and water. Experimental group of animals was feeding with high-fat diet. High fat diet was preparing by adding 30 % of sunflawer oil to standard food. After that, in the terms of energy, the high-fat diet contained 30% carbohydrates, 16 % protein and 54 % fat. Control group of animals was feeding with standard food containing 57 % carbohydrates, 32% protein and 11 % fat. The experiments were lasted 3 weeks. The principles of animal care (NIH publication No. 85-23, revised 1996) were applied. The rats were anaesthezed with Phenobarbitol (10 mg/100 g body weight). Light and electron microscopy The liver was removed and cut in blocks. The part of blocks of the liver tissue was immediately frozen and cut to 10 μ m thick section. The frosen sections were stained with H and E as well as with Sudan IV, Sudan III i IV and Oil Red O for neutral lipids. The liver tisse blocks were also fixed in Carnoy and Boiun , procesed in a standard way for light microscopy and stained with H and E. The other part of the liver tissue was cut in blocks with sides of about 0.5 mm, which were placed in mixture of 2, 5 % glutaraldehyde and 0, 8 % paraformaldehid in 0, 1 M phosphate buffer. The specimens were postfixed in 1% osmium tetroxside, dehydrated and embedded in Durcopan. 1μ m-thick semithin sections were cut and stained with toluidin blue. Preparation of hepatocyte culture and glucose production Hepatocytes were isolated by a collagenase perfusion technique and cultured for 24 h in M199 serum– free medium. Glucose production was measured by incubation the cultures in glucose-free Hanks-Hepes medium with the addition of 10 mmol/l pyruvate. The glucose released into the medium was determined enzymatically with glucose oxidase. Results All rats treated in our experiment with fat-rich diet (sunflower oil) presented a steatotic liver. The area of diffuse steatosis were exchanged with focal steatosis ( in periportal hepatocites). The liver cells occupied by fat were distended, while hepatic sinusoids between them were narrowed. The glucose production in hepatocytes isolated from rats on high fat diet was 79% higher compared with controls on standard diet. Conclusion The liver of animals feeding with high fat diet (sunflower oil) showed steatosis already after 3 weeks of experiment. This indicate that high sunflower diet induce the change in morphology as well as in metabolsm of hepatocytes.

high fat diet ; hepatic steatosis

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