动物造模,股骨头缺血性坏死动物模型 z-bio 2021-12-04 624

　　1 Liquid nitrogen freezing method

　　(1) Reproduction method Anesthetize the experimental dog by intravenous injection of pentobarbital sodium weighing 30 mg/kg, and make a posterolateral incision on one and the proximal end of the animal's hind limbs. The femur was exposed directly. , Cut the round ligament and dislocate the femur. To prevent frostbite, wrap the surrounding soft tissues in sterile gauze and cotton pads, inject liquid nitrogen into the femoral head for about 2 minutes to replenish the femoral head, and then suture the joint capsule to maintain the stability of the joint.

　　(2) Model characteristics 1 to 3 days after the operation, bone marrow tissue edema and coagulative necrosis of hematopoietic cells can be seen under the animal microscope, 5 to 7 days after the operation, the necrosis of bone cells and osteoblasts disappeared, and many red blood streaks disappeared. The cells disappeared. There was thrombosis in the blood vessels leaking from the medullary cavity and hematopoietic stem cells. 12 days after the operation, the osteoblasts became thin, ruptured, collapsed and became inflamed. Further osteonecrosis occurred 19 to 33 days after the operation. It collapses, fractures show granular changes, small blood vessels and fibroblasts grow into necrotic areas, form new bone, matrix reaction occurs, and collagen fibers are gradually formed.

　　(3) Comparative medicine Human aseptic necrosis of the femoral head is divided into two types: traumatic and non-traumatic. The reason for the former is clear, but the reason for the latter is not yet fully understood. All the basic pathological changes without vascular necrosis of the femoral head are the same. In other words, the first is bone cell necrosis, and then the repair response. The model was established by liquid nitrogen freezing, and its lesions range from necrosis to changes in the bone marrow during repair. It is a disease with no vascular necrosis of the femoral head caused by the interruption of blood supply and freezing, reflecting the changes in the body. The initial stage is necrosis of bone and bone marrow cells. Edema is caused by blood blockage, increased pressure after freezing, and venous congestion caused by tissue fluid leakage.

　　2 hormone method

　　(1) The replication method experiment was conducted 2 weeks before and after the last injection, and within 2 weeks after the last injection, the rabbit was first injected with 10 ml/kg of horse serum. Horse serum injection, 40 mg/kg body weight per day, intraperitoneal injection of methylprednisolone for 3 consecutive days.

　　(2) Model features: The empty trabecula and intramedullary fat cells of the model animal can be seen within 8 weeks of modeling. Within 16 weeks, the necrotic trabecular bone of the empty trabecular bone fractured, revealing isolated bone fragments. Intramedullary fat cells swell and fuse into thin slices. Within 24 weeks, the trabecular bones became thinner, the distance between the trabecular bones increased, the isolated sections were deeply stained, the structure became blurred and uneven, and the hematopoietic bone marrow was replaced. Depends on adipose tissue. At each stage, the structure of the vascular wall of the vegetative arterioles is not clear. Some blood vessels are filled with reticular fibers, and red thrombus formation can be seen. The number of blood vessels is significantly reduced and the scope is wide. Scanning electron microscopy of the bone marrow region showed that the collagen fibers on the surface of the bone matrix became disordered within 8 weeks, and the fibers were loosened in a large amount. There are almost no osteoblasts on the surface of the trabecula. At 16 and 24 weeks, the trabecula ruptures and collapses, and the collagen fibers on the surface of the bone matrix relax. According to transmission electron microscopy, bone cells are in the stage of degeneration and necrosis within 8 weeks. The degeneration of bone cells mainly means that the organelles in the cytoplasm are swollen, the organelle structure is blurred or the organelle membrane structure is lost, and the bone cells are mainly necrotic bone cells. Such as nuclear abscess. , Heterochromatin concentration, nuclear division, cell division, degeneration bone cells occasionally contain lipid droplets; degeneration and necrosis bone cells increase at 16 weeks, the number of degeneration bone cells increases lipid droplets; 24 within a week, most of them are Degeneration and necrosis of bone cells at this stage. The cell volume occupies the entire bone cleft. The cells have huge lipid droplets. The nucleus is squeezed to one side, looking like a crescent moon. Heterochromatin is enriched, with nuclear condensation, fragmentation and destruction. , Fat droplets can be seen in bone cells.

　　(3) Comparative medicine Corticosteroid-induced avascular necrosis of the femoral head accounts for the majority of non-traumatic osteonecrosis, mainly young and middle-aged, most of which are bilateral and affect the lives of patients. In the past, the clinical manifestations of animal models of hormone-induced avascular necrosis of the femoral head were completely different from those of humans. This model first uses horse serum to induce type III allergies in rabbits. Antigen-antibody complexes deposit on the walls of blood vessels, causing irritable vasculitis. At the same time, it uses glucocorticoids to inhibit the synthesis of collagen and elastic fibers. Damage to the blood vessels of existing vasculitis will aggravate vasoconstriction, promote platelet aggregation, inflammatory proliferation of endothelial cells, rupture of middle elastic fibers, rupture or embolism of small arteries, and intramedullary hemorrhage.