动物模型,脾功能亢进 z-bo 2020-08-10 597

　　Hypersplenism (hyperslenism) is a clinical syndrome and one of the most common manifestations of patients with liver cirrhosis. The main clinical manifestations are splenomegaly, one or more types of blood cells are reduced, and bone marrow hematopoietic cells proliferate accordingly. The direct consequence is the disorder of the body's blood coagulation mechanism and the decline of immunity.

　　Canine hypersplenism model

　　(1) Reproduction method For experimental dogs weighing about 15kg, the animals are fasted with water for 14 hours, and then the skin is prepared on the abdomen, and Sumianxin general anesthesia is injected intramuscularly at a dose of 0.1ml/kg body weight, intravenous access is established, and intraoperative fast input balance Liquid 500ml, operation under aseptic conditions: first ligate the main splenic vein at the entrance vein of the splenic vein, and then ligate the dilated branches of the splenic vein at the splenic portal (to avoid the establishment of splenic vein collateral circulation). They were reared under routine conditions after surgery, with free drinking and eating. The animals were anesthetized again in the second week after operation, and the splenic vein collateral vessels were ligated by laparotomy. Perform abdominal CT or ultrasound examinations every week after surgery to understand the changes in the size (thickness and long diameter) of the spleen; before and every week after the operation, the animal’s peripheral blood was collected for white blood cell, red blood cell and platelet counts. Animals were killed by excessive anesthesia within a predetermined time after the operation. The spleens were fixed with 10% formaldehyde, embedded in paraffin, and made conventional tissue sections, stained with HE, and observed under light microscope.

　　(2) Characteristics of the model The red blood cells and platelets of the model animals decreased in the first week after splenic vein ligation, and the platelets and red blood cells decreased significantly at the third week; the platelets and red blood cells remained at low levels until the 9th week when the animals were sacrificed. During the observation process, the white blood cell level of model animals did not change significantly. The postoperative CT examination showed that the spleen volume increased significantly. At the second week of laparotomy, the spleen was slightly reduced, and several branches of the splenic vein appeared around the splenic hilum. After re-ligation, the spleen hilum showed only a small network of tortuosity. Venous network, no thick veins with obvious expansion. Microscopic histological observations showed that the spleen of the model animals was obviously congested and the splenic sinus was enlarged and congested at the end of the second week. A large number of hemosiderin macrophages formed after the destruction of red blood cells were seen. The splenic sinus was removed from the spleen at 4-6 weeks. In addition to the expansion, fibrous tissue proliferation can still be seen, there are microthrombi in the splenic sinus, the white pulp or lymph nodes in the spleen are significantly reduced, the splenic trabecula is thickened, and the splenic capsule thickens. The model is simple to make, has a short operation time and a long duration, and can be replicated with large animals. However, the use of splenic vein ligation can not cause the leukopenia of the model animals, so this model can not show the characteristics of hypersplenism leukopenia.

　　(3) Comparative medicine Hypersplenism is portal hypertension caused by liver cirrhosis after hepatitis. It is mainly manifested as splenomegaly and reduction of one or more lines of auto cells, red blood cells and platelets in peripheral blood, leading to disorders of the body's blood coagulation mechanism and immunity decline. Splenectomy is the most commonly used method for the surgical treatment of hypersplenism in clinical practice, and its curative effect is definite. However, with the deepening of the understanding of the immune function of the spleen, it has been recognized by clinicians to preserve part of the spleen function as much as possible. At present, selective splenic artery embolization, intrasplenic ethanol injection and other minimally invasive methods are gradually used to treat secondary hypersplenism, but the clinical effect is not satisfactory. The former is prone to splenic abscess, and the embolization range is difficult to control in the latter. It is of great significance to establish an ideal splenomegaly animal model for experimental research on minimally invasive treatment of secondary hypersplenism. Clinically, the method of radiofrequency ablation is being explored. Because the size of the spleen of dogs is ideal, it can meet the needs of experiments. The splenic vein ligation method can reduce the red blood cells and thrombocytopenia of the model animals, and cause pathological changes in the spleen tissue. The hypersplenism model can be successfully established, and the hypersplenism state of the model animals can be maintained for more than 9 weeks. Previous studies have reported that intraperitoneal injection of methylcellulose and gelatin sponge can also induce secondary splenomegaly and hypersplenism in rats, but the model induction time takes 6 to 8 weeks, and the small animal model simulation clinical study has its limitations. This model can be used as an ideal model for hypersplenism surgery or interventional therapy.