动物造模,药效评价,肝硬化 z-bio 2024-08-22 597

　　(1) Method of replication: Adult male rats were intraperitoneally injected with 2ml/kg body weight of 30% CCl4 paraffin oil solution twice a week for 7 consecutive weeks. Alternatively, 3ml/kg body weight of 40% CCL4 soybean oil solution can be subcutaneously injected, with the first dose of 5ml/kg body weight, once every 3 days, for a total of 14 times. During the first 2 weeks of the experiment, a mixed feed of 80% corn flour and 20% lard was fed. After 2 weeks, 0.5% cholesterol was mixed into the feed, and 30% ethanol was used as the sole beverage for 42 consecutive days. Subcutaneous injection of 3ml/kg body weight of 50% CCl4 soybean oil solution, with the first dose of 5ml/kg body weight, every 4 days. From the 5th dose onwards, intramuscular injection will be used for a total of 15 times. During this period, 10% ethanol will be consumed instead of drinking water, and regular pellet feed will be fed for 60 consecutive days. Alternatively, 60% CCl4 mineral oil solution can be subcutaneously injected at a dose of 3-5ml/kg body weight, once every 4 days, for a total of 15 doses. The first 4 doses are 5ml/kg body weight, 5-11 doses are 3ml/kg body weight, and 12-15 doses are 5ml/kg body weight. Additionally, 10% ethanol is used as the sole drinking water for 66 consecutive days. During the modeling process, the general activity status of the animals is observed daily, and their body weight is measured weekly. After the modeling is completed, whole blood is extracted to prepare serum, part of the liver tissue is weighed to prepare homogenate for biochemical testing, and organs such as the liver and spleen are harvested and weighed to calculate organ coefficients and perform histological examination.

　　(2) During the observation process of model production, the model animals showed signs of lethargy, loss of appetite, drowsiness, irritability, and occasional biting and attacking each other. Their weight first decreased and then increased. Animals injected with 30% CCl4 solution intraperitoneally showed a significant increase in serum alanine aminotransferase (ALT), total protein (TP), globulin (GLO), total cholesterol (TC), triglycerides (TG), and liver tissue TC, TG, and L-hydroxyproline (HPA) levels after 7 weeks of modeling, while serum albumin (ALB) levels and albumin/globulin ratio (A/G) decreased significantly; Under light microscopy, all model animal liver tissues showed fibrosis, with most forming pseudolobules; Under electron microscopy, the ultrastructure of liver cells in model animals is significantly abnormal, with varying degrees of swelling, partial rupture of liver cell membranes, expansion and rupture of endoplasmic reticulum, common large lipid voids, increased electron density of mitochondrial matrix, disappearance of ridges, and the presence of neutrophils in the hepatic sinusoids. Subcutaneous injection of 40%, 50%, and 60% CCl4 solution for 42-66 days resulted in a survival rate of 46% -77% in animals and a success rate of 72% -100% in liver cirrhosis models. The normal liver tissue of the model animal was destroyed, and the original hepatic lobule was divided and wrapped into circular shapes with different sizes by the widely proliferated fibrous tissue, forming false lobules. The arrangement of liver cell cords in the false lobules is disordered, with the absence, displacement, or presence of two or more central veins in the lobules. Regenerated liver cell nodules have disordered arrangement of liver cell cords, with large cell bodies, nuclei, and dark staining. Liver cells also exhibit bubble like changes and steatosis.

　　(3) Comparative medicine CCl4 is the earliest and most widely used chemical drug for inducing animal models of liver cirrhosis. CCl4 is activated by hepatic microsomal cytochrome P450 to generate carbon trichloride (CCl3), which attacks phospholipids on the membrane structure of liver cells, causing lipid peroxidation and damaging the membrane structure of cells; CCl3 also forms covalent bonds with intracellular proteins, damaging mitochondria and reducing the production of reducing coenzyme A (NADH) and adenosine triphosphate (ATP) in the liver. Fatty acid oxidation is inhibited, affecting the tricarboxylic acid cycle and leading to "suffocation" death of liver cells; The deformation and destruction of endoplasmic reticulum, mitochondria, Golgi apparatus, and even cell membrane can lead to obstacles in protein synthesis, energy metabolism, and lipid oxidation. Triacylglycerol and fatty acids accumulate in liver cells, leading to steatosis, hepatocyte necrosis, and fibrosis. High concentrations of CCl4 mainly affect the central nervous system, while repeated use of low concentrations can damage the liver and kidneys. Liver damage repair damage ultimately leads to cirrhosis. CCl4 induced liver cirrhosis model is usually used, with a concentration of 30% to 60% as the modeling solution, and rats as the modeling objects. Various methods such as subcutaneous or intraperitoneal injection, gavage, steam inhalation, or feeding mixed with food are introduced into the animal body. Among them, subcutaneous injection is the most commonly used, but due to its rapid absorption into the systemic circulatory system, subcutaneous injection is more toxic to the brain and kidneys, and the injection site is prone to invasive abscesses and ulcers, with a mortality rate of up to 30% to 40%; Due to the high concentration in the portal vein, intraperitoneal injection results in a short model formation time, but the animals still exhibit a high mortality rate (20% to 35%); The gavage method can directly absorb CCl4 into the liver, but it has a large gastrointestinal reaction and is prone to damaging the esophagus during operation; Although the steam inhalation method absorbs quickly, it has strong respiratory irritation, high toxicity to the central system, animal intolerance, and is prone to environmental pollution and injury to laboratory personnel; Due to the ability to dissolve the modeling drug in a small amount of food for rapid oral administration, the mixed feeding method can control its concentration or reduce its irritation to the gastrointestinal tract by eating small meals multiple times. However, due to the influence of animal appetite, the actual intake dose is difficult to grasp, and the experimental period is long with unclear endpoints.