疾病动物模型,急性肝功能衰竭模型 z-bio 2022-01-13 625

　　Acute liver failure (ALF) is a clinical syndrome caused by large-scale hepatocyte necrosis in a short period of time. It is usually characterized by coagulopathy, extensive and extensive hepatocyte necrosis, hepatic encephalopathy and multiple organ failure. Higher mortality rate. Detailed research on its etiology, development and evaluation of new therapies is still an urgent problem. The establishment of large animal models of acute liver failure is essential for studying this disease. The ideal ALF animal model should include the following features: reversibility, reproducibility, duration of treatment window, large animals (which can be used for continuous monitoring and establishment of cardiopulmonary bypass to guide clinical application and efficacy evaluation), and a consciousness model that helps evaluate encephalopathy . It is the least harmful to the environment and testers, has a metabolic physiology similar to humans, and conforms to ethical standards. Currently, surgical or chemical injury methods are mainly used to establish animal models.

　　1. Complete or partial liver resection model

　　(1) Total liver resection model: Pigs have been used to create animal models of total liver resection. The procedure is as follows. Before anesthesia, prepare animals without food and water before the operation. After anesthesia, spread the sterile drape and insert the upper abdomen into the abdomen through the midline or diagonal incision of the upper right abdomen. After gross liver resection, use a temporary bypass device (more common in early models) for reimplantation of the posterior vena cava, portal vein, and portal vein, as well as portal shunt (recently multiple vessels), and cut all perihepatic ligaments, including shunt repair And liver resection and reconstruction). During surgery, fluids should be used to maintain hemodynamic stability, and antibiotics should be used daily to prevent infection after surgery. After the model is successfully established, blood samples should be collected regularly to monitor changes in values such as general characteristics, vital signs, and intracranial pressure, and to observe changes in clinical biochemical indicators. Experimental results show that the total hepatectomy model may change clinical biochemical parameters, increase intracranial pressure and neurological symptoms. These are clinically equivalent to symptoms caused by early liver transplantation failure, such as liver resection or tumors. Researchers who rely on this model will gradually understand the pathophysiological response and nervous system changes of acute liver failure after total hepatectomy, and can also be used to study artificial biological liver support systems. Therefore, the porcine total liver resection model is an accepted model for testing the usefulness and function of various temporary support systems. Its main advantages are: it is used to understand the status of total hepatectomy, study encephalopathy, and study the treatment methods of total hepatectomy. Test various artificial biological support systems. Disadvantages are: high surgical technology requirements and irreversible; narrow treatment window; liver necrosis, hepatic toxin and liver failure caused by the release of inflammatory factors in the damage process and lack of related pathophysiological changes; abnormal changes in biochemical indicators are mild, liver Sexual encephalopathy appears late; surgical injury affects the pathophysiological state.

　　(2) Partial liver resection model: The principle of this model is to remove most of the liver and cause insufficient liver function. The surgical procedure is the same as that of the total liver resection model. During the operation, 70% to 80% of the liver will be removed with or without portal vein shunt, including the left side, left anterior, right side, and caudal lobe. During the operation, changes in clinical biochemical indicators should be observed, and liver tissue should be sampled for histopathological examination. The partial liver resection model is clinically equivalent to most liver resections, such as liver tumors. It is suitable for studying the symptoms of liver failure, biological liver support system and liver regeneration. Its main advantage is: it can simulate the biochemical changes of acute liver failure and the emergence of encephalopathy, and it has certain reversibility. It can be used to study liver regeneration and test various artificial biological support systems. The main disadvantages are: different liver tissue resections, different degrees of liver injury and acute liver failure, higher surgical technical requirements, liver regeneration will affect reproducibility, and special circumstances such as infection or residual liver tissue bleeding may be injured. The late surgical injury reaction will affect the observation and can not fully reproduce the release of inflammatory factors and the release of inflammatory factors in acute liver failure, as well as the pathophysiological changes of hepatocyte necrosis, not; lack of neurological symptoms. Currently, hepatectomy combined with liver ischemia or hepatectomy combined with liver chemicals are commonly used for modeling.

　　2. Compared with the liver resection model, the liver ischemia model has more research purposes. The most commonly used modeling method is: the preoperative anesthesia method is the same as before. The surgical procedure is as follows: first perform portal vein shunt, open the abdomen to release the portal vein and inferior vena cava, end-to-end or left-to-right anastomosis (such as direct anastomosis or catheter bypass) equipment); then the hepatic artery and other hepatic blood vessels should be obstructive and Ligation or clamping of the hepatic artery in shunt surgery is performed in the later or first stage. Most of them choose to combine common hepatic artery and collateral circulation ligation, and they can also ligate hepatic vessels, gastroduodenal arteries and all their collaterals at the same time. During the operation, the changes in clinical biochemical indicators must also be observed, and special attention should be paid to the necessity of maintaining body temperature during the modeling process to reduce fluctuations. The hepatic ischemia model is divided into complete and temporary blood flow block according to the method of hepatic artery occlusion (permanent or temporary) after portal vein shunt. The main advantage of the permanent ischemia model is that it may show progressive encephalopathy, coma, and is suitable for studying neurological symptoms. Suitable for research and testing of artificial biological liver support system. The main disadvantages are: irreversible, high surgical skills, and narrow treatment window. The main advantages of the transient cerebral ischemia model are: incomplete blood flow block has a certain reversibility, is not suitable for hypothermia treatment, is suitable for liver regeneration research, and has all the advantages of a permanent ischemia model. At the same time, it can display liver necrosis in situ and has a longer survival period, which is the most obvious advantage over the permanent ischemia model. The main disadvantages are high requirements for surgical skills and poor surgical response. Generally speaking, the longer the interval between portal vena cava anastomosis and hepatic artery ligation, the longer the animal’s liver failure and survival. The key to modeling lies in the portal, as new collateral flows will occur during this period. .-The time interval between lumen anastomosis and hepatic artery ligation. The surgical ALF model research report shows that in terms of survival time, technical difficulty, safety, reproducibility, reversibility, ALF etiology and treatment research, the liver ischemia model is more practical and widely used than the non-liver model. This model is mainly used. It is used to research and test various biological liver support systems. The partial hepatectomy model is mainly used to study insufficient liver function and biological liver support system. The porcine liver ischemia model is widely used in the research and testing of various artificial liver support treatment equipment, as well as the study of the occurrence and onset mechanism of acute liver failure.

　　3. The currently commonly used drug induction models for hepatotoxic chemicals are acetaminophen and D-galactosamine. There are other reports on the use of carbon tetrachloride, thioacetamide, lipopolysaccharide, adamantacin-α, etc. Among them, acetaminophen is a hepatotoxic drug, and its excessive use is an important cause of ALF in Europe and America. The canine acetaminophen induction model has been widely used. D-galactosamine is often used to induce miniature pigs. D-galactosamine is a hepatotoxic drug selective for amino sugars. The most commonly used modeling method is: first anesthetize the animal, then prepare the D-galactosamine solution and choose the route of administration. It is prepared by dissolving 1.0-1.5 g/kg of D-galactose hydrochloride in a 5% glucose solution. The drug was controlled to 0.05 g/ml, and the pH of the solution was adjusted to 6.8 with 1 mmol/L sodium hydroxide solution. Filter before use to ensure that the prepared solution is used within 2 hours. Establish drug delivery channels. The external jugular vein is inserted into the central venous catheter for drug delivery, blood sampling and central venous pressure measurement. Changes in clinical biochemical indicators and histological examination should be observed. Liver tissue was collected intermittently before and after administration. The D-galactosamine model can better simulate the pathophysiological process of the occurrence and development of clinical ALF, and is widely used in the study of artificial biological liver support systems and the study of the mechanism of ALF disease. The main advantages of this model are reversibility, stability and many symptoms, as well as good reproducibility, low exotoxins and viral liver failure, which well reflect the clinical characteristics of ALF. Main shortcomings: potential harm; high modeling cost; types and individual differences, great variability; limitations of encephalopathy research; lack of a comprehensive understanding of D-galactosamine-induced liver failure. In short, this model has some shortcomings, but compared with other liver chemistry models, it is an ideal model. It is very similar to the clinical features, biochemical and histopathological changes of ALF, and has similarities, extensive research and application.

　　Four. Artificial liver research Artificial liver support system is a device made of biological materials or liver cells that can replace liver functions, such as detoxification and synthesis. According to its nature, it can be divided into two types: biological type and non-biological type. Bioartificial liver is an artificial liver support system, which combines organs, tissues and cells of the same or different animals with special materials and devices to form an artificial liver support system. The main cell materials for bioartificial liver research are human hepatocytes, hepatocellular tumor cell lines and porcine hepatocytes. However, due to the lack of human hepatocyte sources and the potential instability of tumor cell lines, the cultivation of porcine hepatocyte bioartificial liver has gradually become the main purpose. Research and clinical application of artificial liver. Bioartificial liver is an effective treatment and support system for fulminant liver failure, chronic severe hepatitis and other diseases. Researchers have established a hybrid artificial liver support system that uses a bioreactor containing more than 5 x 109 porcine liver cells combined with plasma exchange equipment to be an effective aid and treatment method for chronic severe hepatitis. On the basis of comprehensive treatment, the researchers also mixed an artificial liver composed of plasma exchange, plasma adsorption/blood perfusion, continuous renal replacement therapy and a hollow fiber tube bioartificial liver of pig hepatocytes effective for severe viral hepatitis. I use The liver support system. The patient's liver failure has an obvious supporting effect, is well tolerated, and can significantly improve the cure rate and improvement rate of severe hepatitis. Other researchers use plasma exchange equipment, medicated activated carbon perfusion equipment and bioreactors to cultivate human or pig liver cells to form a hybrid bioartificial liver support system. The constructed hybrid bioartificial liver support system has obvious liver support effects on liver failure. It is used as an effective method to treat severe hepatitis. Currently, as mentioned above, some scholars have used nonwoven bioreactors to inoculate pig primary hepatocytes to construct bioartificial livers and treat D-galactosamine-induced swine fulminant liver failure models, thereby improving the method. The liver is built on a bioreactor woven with non-woven fabrics, which has obvious liver support for fulminant liver failure and has clinical application potential.