动物模型,诱发肝硬化 z-bo 2020-08-07 539

　　(1) Reproduction method Adult rats were anesthetized by laparotomy through a midline incision in the supraumbilical abdomen, and the common bile duct was sutured with 7-0 silk suture 1 cm from the hilum. After the operation, they will be kept for 2-8 weeks. During the period, pay attention to observe the general activity status and physical signs of the animals, and dynamically collect blood from the orbit to prepare serum for alanine aminotransferase (ALT), total bilirubin (TBIL), alkaline phosphatase (ALP), hyaluronic acid (HA) content Detection. After the modeling is completed, the liver is removed and weighed, and part of the tissue is cut to prepare a homogenate for the content of hydroxyproline (Hyp), total protein (TP), malondialdehyde (MDA), and superoxide dismutase (SOD) For determination, part of the tissues were fixed with 10% formaldehyde solution, embedded in conventional paraffin, sections were stained with HE or Masson, and part of the tissues were fixed with 4% glutaraldehyde and 1% osmium tetroxide, and 618 epoxy resin conventionally coated Embed, prepare slices with ultra-thin microtome, uranium-lead double staining, and use light microscope and electron microscope for histological examination.

　　(2) Characteristics of the model After modeling for 5 weeks, the wet weight and coefficient of liver and spleen of model animals increased significantly, serum ALT, TBIL, ALP, liver tissue Hyp, MDA increased, liver tissue TP, SOD decreased. Light microscopy showed that 1 to 2 days after operation, the liver tissues of model animals gradually appeared scattered degeneration, necrosis and inflammatory cell infiltration, which became very obvious at 3 days. At the same time of the above changes, small bile duct-like epithelial cells appeared in the periphery of the lobules in the portal area, and gradually expanded, extended, and deepened into the lobules over time, and the lobules became flower-shaped. At 35 days, the small bile ducts and the accompanying fibroblasts, collagen fibers and capillaries form a membranous space, which is interconnected, surrounded, and divided with adjacent hyperplastic spaces until pseudolobules are formed. Electron microscopy showed that on the 1st and 2nd day after operation, there were single or 2 to 3 hepatocytes in the periphery of the lobules which showed scattered atrophy and degeneration, the nucleus was pyknotic, the cytoplasm was dense, and the organelles were degenerated, and it was soluble on the 3rd day. Necrosis, and see inflammatory cell infiltration, phagocyte buildup. At the same time of hepatocyte degeneration and necrosis, small bile duct-like epithelial cells appeared and proliferated in the periphery of the lobules, and the basal side of the vesicular structure had basement membrane and collagen fiber layer. At 1 to 2 weeks, the small bile duct-like epithelial cells further proliferate and gradually develop and extend from the periphery of the lobule along the hepatocyte cord to the inside of the lobule. After 3 weeks, the small bile duct-like epithelial cells were clearly differentiated and evolved. Most of them appeared to differentiate into small bile ducts. The epithelial cells became cubic or flat, the intermediate filaments in the cytoplasm increased, and the nuclear membrane was sunken to form irregular shapes. The chromatin aggregates under the nuclear membrane, the lumen is enlarged, and the microvilli are sparsely distributed. The proliferation of collagen fibers around the small bile ducts gradually formed a clear layer of collagen fibers. The proliferating small bile ducts and the accompanying phagocytic cells, mast cells, inflammatory cells, fibroblasts, capillaries and proliferating collagen fibers together form the partition between hepatocytes. There are also a few small bile duct-like epithelial cells that differentiate and evolve toward the hepatocytes, and the transitional cells and hepatocytes in the form of vesicles. It is often wrapped with a clear layer of collagen fibers to form small hepatocyte nodules. At 8 to 12 weeks, it showed typical collagen fiber proliferation and hepatocyte nodules.

　　(3) Comparative medicine Extrahepatic bile duct obstruction can cause bile duct dilatation, cholestasis, and increased pressure in the bile duct above the obstructed site, and can cause intrahepatic bile duct dilatation and rupture, leading to ischemia and necrosis of liver cells, and eventually develop into biliary liver fibers And liver cirrhosis. Common bile duct ligation can completely obstruct the bile ducts of model animals, block bile excretion, and accumulate in the gallbladder, induce the production of free radicals in the liver, cause lipid peroxidation of cell membranes (increased MDA, decreased SOD), and lead to cell structure damage. Increased permeability and imbalance of cell metabolism. Lipid peroxidation causes a chain reaction, which further aggravates liver cell damage and necrosis (decreased TP). The ischemia and necrosis of a large number of liver cells induce the appearance of small bile duct-like epithelial cells. The latter may be proliferated by a kind of stem cells with multi-differentiation potential, and have proliferation and differentiation functions. In the case of liver parenchymal necrosis of liver damage, small bile duct-like epithelial cells differentiate and evolve into vesicular or nodular hepatocytes on the one hand, on the other hand, synthetic collagen participates in the proliferation of collagen fibers (increased Hyp), which accelerates Formation and development of liver cirrhosis. This model can better simulate the process and results of human liver fibrosis and cirrhosis caused by long-term cholestasis, and the modeling method is simple, the cycle is moderate, the repeatability is good, and the success rate is high. At present, in addition to rats, rabbits, dogs, monkeys and other animals with common bile duct ligation induced biliary cirrhosis models have been successful and have been widely used at home and abroad.