动物造模,药效评价,肝衰竭 z-bio 2024-09-02 540

　　(1) Model method: Adult animals were anesthetized and fixed, and laparotomy was performed along the midline of the abdomen. A purse string suture was performed on the inferior vena cava above the renal vein using 5-0 vascular suture. After finding the portal vein from the root of the mesentery of the small intestine, it dissociates from the hepatic portal to the level of the splenic vein, and then ligates and cuts off the collateral branches of the portal vein. Intravenous injection of heparin 100U/kg body weight. Clamp the portal vein horizontally at the splenic vein level, and then clamp, cut, and ligate below the hepatic portal fork of the portal vein. Insert a shunt tube containing anticoagulant into the portal vein below the level of the splenic vein and ligate it for fixation. Insert it into the inferior vena cava through a purse string and tighten the purse string suture. Before inserting into the inferior vena cava, use non-invasive vascular forceps to block the blood flow of the inferior vena cava above and below the purse string suture. Free the common bile duct from the hepatoduodenal ligament, and then double ligate the hepatoduodenal ligament tightly against the duodenum to block all hepatic arteries. After laparotomy, the portal vein and inferior vena cava can be freed for end-to-end or side to side anastomosis, and then the hepatic artery can be occluded on this basis. Rats can temporarily clamp the hepatic artery with a vascular clamp, while experimental dogs or pigs can undergo a second surgery 24 hours after portal vein anastomosis to temporarily clamp the hepatic artery for 4-6 hours. Throughout the entire model making and experimental process, the blood pressure, pulse, and consciousness of the animals were continuously observed, and their time of death was recorded. At the same time, blood was dynamically drawn to prepare serum for liver function testing, and liver tissue was harvested for morphological examination.

　　(2) The characteristics of the model are that after 30-60 minutes of complete blockage of blood flow into the liver, the animals begin to be restless and gradually enter a state of hepatic coma. Systolic pressure gradually decreases with time, and all animals die within 75-155 hours. The liver of dead animals appears dark red, dull, and scattered with purple patches. After the interruption of hepatic blood supply, animal serum ALT, AST, LDH, and NH3 showed a progressive increase, PT gradually prolonged, while fibrinogen (FIB) and GLU gradually decreased. Under the microscope, after 2 hours of hepatic blood flow obstruction, the Diess gap significantly expanded, the central vein collapsed, the cytoplasm of liver cells showed vacuolar degeneration, the nucleus shrank, the nucleolus disappeared, the glycogen granules in the cytoplasm were homogenized, the rough endoplasmic reticulum was degranulated, the mitochondria were swollen and partially dissolved, the chromatin in the nucleus was aggregated, the nucleus was deformed, and pseudo inclusions were formed in the nucleus; The structure of liver lobules in animals with liver failure is unclear, the arrangement of liver cells is disordered, the liver plates are dissociated, and focal and patchy liver cell necrosis can be seen.

　　(3) The comparative medicine acute liver ischemia model is currently an ideal animal model for inducing acute liver failure, and its surgical steps include portal vein anastomosis and hepatic artery ligation. Among them, hepatic artery ligation includes two methods: complete ligation and temporary clamping. The former refers to the complete clamping or ligation of the portal vein and hepatic artery, which is a model of complete blood supply obstruction. This model animal generally has a short time to death, similar to the characteristics of a liver removal model, and is irreversible. Therefore, it is only suitable for short-term evaluation of in vitro bio artificial liver support systems or for studying changes in intracranial pressure and brain edema related to acute liver failure. After undergoing portal vein anastomosis, the latter temporarily clamps the hepatic blood vessels using clamps or suspension wires, and releases them after acute liver ischemia leads to liver function failure, restoring blood supply to the liver. This is a temporary ischemic model. The interval between anastomosis and hepatic artery ligation determines the occurrence of more or less collateral circulation, and the latter is significantly correlated with the degree of acute liver failure and the time of death in animals. Therefore, the interval between anastomosis and hepatic artery ligation is the key to the preparation of this model. Due to its potential reversibility, this model is suitable for long-term biological artificial liver support experiments and observations. At present, this method is widely used in animal experiments of biological artificial liver, which is currently the most ideal surgical model.