动物造模,佩尔斯特病动物模型 z-bio 2021-11-03 521

　　Perthes disease refers to avascular necrosis of the femoral head in children, which is part or all necrosis of the femoral head epiphysis caused by blood flow disorder of the femoral head. The flattened deformity of the femoral head is often left after the lesion is stationary, which affects the function of the hip joint.

　　(1) Reproduction method After anesthetizing the experimental rabbit with 30% urethane intravenously, it is fixed on the operating table, the left hip is shaved, the skin is routinely disinfected, and a hole towel is used for aseptic surgery. Make a 6cm incision on the posterolateral side of the hip. After cutting the skin, go through the space of the posterior quadratus muscle of the greater trochanter of femur into the deep layer and reach the hip joint capsule. Cut the nodular capsule, cut off the round ligament of the femoral head, and dislocate the femoral head. With a sharp knife, all the supporting blood supply of the femoral neck was cut off and the supporting belt was peeled down to the level of the intertrochanteric line. After it was confirmed that all supporting blood supply of the femoral head was interrupted, the hip joint was reset and the incision was sutured layer by layer. 800,000 U of penicillin was injected intramuscularly after operation for 3 days.

　　(2) Features of the model. The surface of the femoral head was tarnished by naked eyes 2 weeks after the operation, and the cartilage part lost its translucent appearance, which was slightly pale, especially near the stop point of the round ligament of the femoral head. The femoral head was pale and obvious in 4 weeks after the operation, and some were grayish-yellow. X-ray examination showed that the femoral head density of the affected side increased and the epiphyseal height decreased slightly in the 4 weeks postoperative group, and the femoral head density increased and the epiphyseal height decreased significantly at 8 weeks postoperatively. The epiphyseal lines of some specimens were blurred. Bone imaging showed that the radioactive uptake of all specimens increased significantly at 4 and 8 weeks after surgery; MRI showed that the low-intensity area of the femoral head increased, and the signal gradually became uneven, mixed with high-intensity, and the structure of the epiphyseal plate was unclear. Pathological examination showed that the bone lacuna was empty 2 weeks after the operation, the bone marrow tissue was dissolved, fragmented, and disappeared, and fibrogranulation containing undifferentiated mesenchymal cells and capillaries were invaded and began to replace the necrotic bone marrow tissue, but it was not obvious yet. New bone formation; proliferation of undifferentiated mesenchymal cells and capillaries increased in the 4 weeks after surgery, mesenchymal cells differentiated into osteoblasts on the surface of dead bone, new bone began to form on the dead bone, and the articular cartilage matrix appeared light After 8 weeks, there are still mesenchymal cells on the surface of some dead bones that differentiate into osteoblasts, but their repair activity is reduced. Scattered cartilage necrosis can be seen, and the cartilage matrix is lightly stained.

　　(3) Comparative medicine The X-ray manifestations of this model at 4 and 8 weeks after surgery are similar to those of human Persteer's disease, but no epiphyseal fragmentation is found. The rabbit is a four-legged animal. The postoperative pain and weight bearing of the affected limb are reduced, and the stress on the animal is reduced due to caged cages, which may be one of the factors. MRI showed that the low signal range expanded and gradually lost uniformity, indicating the coexistence of osteonecrosis and repair in the model animals at this time, the coexistence of new bone formation and fibrous granulation, resulting in the complexity of the signal, and also a good simulation of the MRI performance of Peelster’s disease . The basic pathological changes and bone imaging of this model also have the characteristics of human Peerster's disease.