动物模型,肝衰竭 z-bo 2020-08-07 539

　　(1) Replication method Adult male mice or rats, after 12 hours of fasting, intraperitoneal injection of D-galactosamine (D-Gal) and endotoxin lipopolysaccharide (LPS) 0.1 at a dose of 800-1000 mg/kg body weight mg/kg body weight. Or adult rats, the endotoxin isoform FS-112 (dissolved in 5% ethylene glycol, 5% ethanol, 5% glucose) 30 mg/kg body weight was injected into the tail vein, and 70% partial hepatectomy was performed 2 days later. Or adult dogs, intravenous injection of 30% acetaminophen (APAP) 180mg/kg body weight, while subcutaneous injection of 40% CCl4, repeated administration in the same route at 9 hours, the dose is half of the first dose. After administration or/and surgery, the general condition and survival of the model animals are continuously observed, and blood is drawn regularly to prepare serum for biochemical testing and liver and kidney function determination. After the model animals die or artificially executed, the liver, heart, Organs and tissues such as lungs and kidneys were examined for pathology.

　　(2) Model characteristics After 3 hours of intraperitoneal injection of D-Gal and LPS, the liver tissue of the model animal began to edema; at 6 hours, the edema was obvious, the liver surface was congested, part of the liver was reduced, the liver capsule was tight and dull, and more hepatocyte cytoplasm Concentration. The nucleus shrinks, the chromatin borders under the nuclear membrane, the mitochondria are swollen, and the intracellular and plasma membrane structures are obviously disordered; at 12h, the liver tissue is severely necrotic, the area of necrosis is significantly increased, the lobule structure is destroyed, and the liver cord is dissociated. Hepatocyte lysis, dilation and congestion in the liver sinusoids, small focal hemorrhage in the interstitium, and inflammatory cell infiltration in the necrotic area and the portal area; at this time, the serum ALT, TBIL, TNF-a, ET-1, IL-6, and NO levels rise. The content of ALB decreased, and the death time of model mice was 8-21h. In FS-112 plus partial liver tissue resection model animals, ALT and TB levels began to increase progressively from 12h to 72h after surgery. After the second injection of APAP and CCl4, the model dogs could not stand, but could still get water and shake their heads. At 12h, 24h, and 43.5h, serum ALT, AST, TBIL, and NH3 levels increased progressively, while ALB levels decreased progressively PT prolonged with time; after 30h, it gradually turned into a state of lethargy. The average appearance time of liver coma was 40.5h. During this period, liver odor was very obvious, and the urine was dark yellow or tea-yellow. Animals died at 41.5h, and the average death The time is 43.5h.

　　(3) Comparative medicine. An ideal animal model of acute liver failure should have six basic conditions: ①Clear features: have physiological, biochemical and pathological features consistent with the clinical, such as large necrosis of liver tissue, liver coma, and death from liver failure. ②Reversible: It should respond to effective treatment, it may promote the development of the disease in a good direction, and may survive. ③Evaluable: The model should have a long enough lesion time from replication to death to ensure that the treatment can be carried out and the efficacy can be evaluated. ④Reproducible: The models replicated at different times and places have basically the same physiological, biochemical and pathological indicators, as well as the time of death, and are comparable. ⑤Practical: According to experimental needs, animals of different sizes can be used for model making. ⑥Safety: Experimental operations and mold-inducing drugs should be safe and less toxic. There are two main types of animal models that meet the above conditions: drug liver injury models and surgical models. The former's modelling agents (liver toxins) mainly include: CCl4, galactosamine, acetaminophen, thioacetamide, lipopolysaccharide, and the latter include acute liver ischemia, total hepatectomy and partial hepatectomy. However, because the above-mentioned methods (single factor) copy models have different model-induced mechanisms, the copied models must have their own characteristics and deficiencies. For example, the course of the total hepatectomy model is irreversible, the operation difficulty and workload of the partial hepatectomy model are too large, the signs of hepatic coma in the CCl4 model are not obvious, the extrahepatic toxicity of the paracetamol model is too large, and the thioacetamide model is too toxic. The model objects are mostly limited to small animals. Although the galactosamine model is an ideal animal model for drug-induced liver failure, the high price of drugs limits its application. In this regard, based on the above-mentioned six basic conditions for model building, some scholars use a combination of different drugs or a combination of drugs and surgery to make liver failure models. This model adopts the method of D-Gal injection and LPS injection at the same time, or S-112 injection before partial hepatectomy, so that the endogenous endotoxemia caused by D-Gal or liver resection can be injected directly with LPS. The exogenous endotoxemia caused has a synergistic effect and increases the toxicity to liver cells. Compared with D-Gal injection or surgical resection alone, the amount of medicine required for modeling is greatly reduced and the rate of liver resection is significantly reduced, thereby significantly prolonging and improving the survival time and molding rate of animals. Similarly, the combined administration of APAP and CCl4 was used to make the model to superimpose the damage of the two hepatotoxic drugs to hepatocytes. Compared with the two drugs used alone, the dose required for the model was significantly reduced, and the extrahepatic toxicity was significantly reduced. In view of this, the method of modeling using compound factors has been widely accepted by people and has become one of the most widely used methods of modeling liver failure.