动物模型,肝衰竭 z-bo 2020-08-07 515

　　(1) Reproduction method Adult male rats, orally give 40% CCl4 oil solution 10ml/kg body weight, or adult dogs, intraperitoneally inject 50% CCl4 oil solution 0.9ml/kg body weight, and observe the animal's coat color, appetite and activity after administration For general conditions, record the time of death, and at the same time regularly or dynamically draw blood to prepare serum for liver function testing, and extract liver tissue for pathological examination. Large animals can still be used for liver B-ultrasound and EEG examination.

　　(2) Model characteristics: The activity of the model rats began to decrease significantly after 12 hours of intragastric administration of CCl4; at 24 hours, they were extremely lethargic, did not eat, and did not resist when being grabbed, their hair was rough, and their urine was yellow; at the same time, ALT, TBIL increased significantly, liver volume increased significantly (individually reduced), yellowish color, fragile texture, large sheet necrosis of liver cells under the microscope, a small amount of neutrophil infiltration in the necrotic area, most of the lobular structure disappeared, and no fibrous proliferation. There is no nodules of hepatocyte regeneration; at this time, some animals have subcutaneous bleeding in the orbit, and animals die; at 48h, the mortality rate of model animals reached 85.7%. In the experimental dogs 2h～3d, all the animals showed different degrees of vomiting, no food, only drinking water, and then reduced activity, slow to respond to external stimuli, then paralyzed, turned into shallow coma, some animals developed high fever and digestive tract Bleeding, jaundice and even progressive exhaustive death. When the medicine was injected for 3 days, the serum ALT, TBIL, NH3, and PT of the model animals were progressively increased or prolonged, while the GLU gradually decreased; EEG examination showed that the general slow wave, Q wave, delta wave, and three-phase wave were visible. ; B-ultrasound examination found that the liver has reduced in size to varying degrees. During the 48-96h period, the mortality rate of model animals reached more than 73.0%. Routine pathological examination after death revealed that the liver of the model animals shrank, the liver capsule shrank, and the color was not uniform; under the microscope, large areas of hepatocytes were lysed and necrotic, the sinusoids were dilated and filled with red blood cells, and there were a small amount of hepatocytes in the peripheral blood vessels of the liver lobules. It was degeneration and congestion, accompanied by a large amount of inflammatory cell infiltration, most of which were lymphocytes, and the proliferation of hepatocytes was not obvious. The liver cells of dead animals were lysed and necrotic, and the heart, lungs and kidneys were swollen to varying degrees, bleeding, necrosis, and inflammatory cells were slightly infiltrated.

　　(3) Comparative medicine CCl4 is one of the most classic drug-induced liver injury modeling toxins. It is mainly metabolized by microsomal cytochrome P450 oxidase in the liver to produce trichloromethyl free agent and trichloromethyl peroxy free agent, thereby destroying the integrity of the cell membrane structure and function, and causing the liver cell membrane to pass The increase in permeability and the exudation of soluble enzymes will eventually lead to the death of liver cells and lead to liver failure. According to the metabolism and liver toxicity mechanism of CCl4, different liver injury models can be replicated. Among them, the dosage and method of administration are the key technology. For replicating acute liver failure models, a large-dose one-time gavage or intraperitoneal injection is often used. For intragastric administration, CCl4 is absorbed through the portal vein system and directly enters the liver; intraperitoneal injection has a large absorption area, and the poison is absorbed quickly and completely. After absorption, it mainly enters the portal circulation and first reaches the liver. In terms of animal selection, rodents often use intragastric administration, while large animals prefer intraperitoneal or intravenous injection. CCl4 replicates the liver failure model, because its toxic mechanism is relatively clear, the price is low, and the experimental operation is convenient and the reproducibility is strong, so it is more commonly used. However, the toxic effect of CCl4 on hepatocytes is due to the generation of oxygen free radicals and lipid peroxidation, which damage the cell membrane. Hepatocytes around the central vein are most vulnerable to damage, which is inconsistent with the tissue characteristics of human hepatocyte necrosis. . Moreover, injecting large doses of CCl4, because it cannot be completely metabolized by the liver, and then damage other organs, especially the lungs and kidneys. In addition, it is difficult to observe clinical signs of deep hepatic coma in model animals.