动物造模,非酒精性脂肪肝 z-bio 2024-01-19 829

　　Method 1

　　1. Animal modeling material: Male SD rats, weighing (150 ± 10) g; Medications: cholesterol, lard, 2% pentobarbital solution.

　　2. Method of modeling: After one week of normal feeding, the animals were randomly divided into two groups. The normal group was fed with regular feed; The model group was fed with high-fat feed, which added 10% lard and 2% cholesterol on top of regular feed. The experimental animals are free to drink and eat, and are housed in cages (5 per cage) in animal laboratories at (20 ± 2) ℃ for 12 hours in both light and dark. Two groups of animals were sacrificed at 12 weeks after the experiment. The method was to fast overnight, and the next day, 1 ml/kg of 2% pentobarbital solution was injected intraperitoneally under anesthesia. Blood was collected from the posterior vena cava and euthanized. The liver was quickly removed, and serum and liver tissue paraffin sections and ultra-thin section specimens were prepared as usual.

　　3. The principle of modeling is to consume a high-fat and high cholesterol diet for a long time, which leads to a significant increase in exogenous fat and an increase in chylomicrons absorbed from the small intestine into the bloodstream. As a result, liver uptake naturally increases. When the amount of triglycerides synthesized by the liver exceeds the transport capacity of liver cells, triglycerides deposit in the liver to form fatty liver.

　　4. General changes after modeling: In the experiment, the model group gained weight faster than the normal group, had a more gentle temperament, and did not like to move. There were no animal deaths in any group. At the end of the experiment, the weight of the model group animals was more than 20% overweight compared to the normal group, and their body weight and liver index (liver wet weight/body weight) were measured × 100%) significantly increased compared to the normal group.

　　5. Biochemical and pathological changes after modeling: Changes in serum lipids: At the end of the experiment, the total cholesterol (TCH) and free fatty acids (FFA) in the model group were significantly higher than those in the normal group, and there was no significant difference in blood TG compared to the normal group.

　　Changes in serum liver function: At the end of the experiment, the serum transaminases (ALT, AST) in the model group were significantly increased compared to the normal group, while there was no significant difference in albumin and albumin/globulin ratio compared to the normal group.

　　Pathological changes in the liver: No abnormal changes observed in the normal liver with the naked eye. The liver volume in the model group significantly increased, with tight capsule and blunt edges. The entire liver was milky yellow, and focal yellow white degeneration lesions were observed, with greasy sections. Under the light microscope, there were no abnormal liver lesions in the normal group of rats. At 10 weeks, the pathological examination showed only mild fatty liver without inflammation or necrosis, so a high-fat diet was continued. At 12 weeks, all animals in the remaining model group showed varying degrees of diffuse hepatic steatosis, with intralobular inflammation, some with portal area inflammation, as well as portal area degeneration and punctate necrosis or necrotic lesions, and even some necrotic lesions fused into patches. Inflammatory cells in liver tissue were mainly infiltrated by monocytes and lymphocytes, with some neutrophils infiltrating, but no liver fibrosis was observed. Lipid changed hepatocytes are most obvious around the central vein, extremely swollen and round, with a significantly increased volume than normal. The cytoplasm is filled with a large number of fat vacuoles, similar to foam cells, with unclear boundaries and narrow hepatic sinuses. The model group showed significant abnormalities in the ultrastructure of liver cells. Hepatocellular cord arrangement