动物模型,牙髓炎 z-bo 2020-08-08 632

　　(1) Replication method E. coli standard endotoxin lipopolysaccharide (Lipopolysaccharide, LPS) is diluted with normal saline to 5mg/ml, filtered and sterilized for use. Male Wister rats weighing 250～300g were injected intraperitoneally with sodium pentobarbital anesthetized at a dose of 30 mg/kg body weight. After anesthesia, the animals were fixed on their back, and their bilateral maxillary molars were routinely disinfected in area A and area B first. For the molars (M1) and the second molars (M2), use a 1/4 ball drill to open the pulp on the occlusal surface, exposing the point of penetration. A cotton ball saturated with LPS solution (experimental group) was treated at M1 of area A at the pulp-piercing point for 30 minutes, then the tooth surface was wiped dry with a sterile cotton ball, and temporarily sealed with glass ion cement. The model animals were sacrificed by bleeding on the 1, 3, 5, 7 and 2, 3, 4, and 5 weeks respectively. The bilateral M1, M2 and part of the jaws were taken, and they were routinely fixed with fixative and decalcified for pathological tissue Section and observe under light microscope.

　　(2) Model characteristics The pulpitis model made by this method was observed under microscope. The early stage (within 7 days) mainly showed congestion of the tissue below the pulpal point, infiltration of inflammatory cells, mainly neutrophils, and tooth formation Essential cell arrangement disorder and degeneration, dental pulp tissue cell degeneration and necrosis, capillary dilation and hyperemia, acute inflammation; in the middle and late stages, it is mainly manifested in the chronic degeneration, necrosis, defense and repair process of dental pulp tissue. This model observes the pathological changes for 5 weeks, from the initial inflammation of the pulp through the formation of dental pulp restoration dentin to the histopathological changes of pulp necrosis, which can well reproduce the occurrence, development and development of pulpitis. The process of pulp defense and restoration. When making the model, the animal needs to be fixed on its back for surgical operation. In order to exclude non-experimental factors from damaging the dental pulp, the pulp opening should be light and fast, and the depth should not exceed 1mm, and cooling water should be used to lower the drilling temperature.

　　(3) Comparative medicine The LPS used in this model is a kind of macromolecular compound that is located on the outer membrane of gram-negative bacteria. Myeloid cells divide and matrix synthesis, and high concentrations have obvious cytotoxic effects on dental pulp cells and can cause cell death. The direct damage of high concentrations of LPS to dental pulp cells may be one of the important pathogenesis of dental pulp disease. At the same time, LPS has an inhibitory effect on the cell cycle. It can inhibit cell proliferation and affect the repair of dental pulp cells. Since endotoxin can be detected in the tissues of clinically infected root canal and periapical disease patients, it indicates that endotoxin has an inflammatory effect on dental pulp and periapical tissue. In this model established with LPS, the animal’s dental pulp can survive for more than 4 weeks, which better reflects the damage and stimulation of LPS to the body’s dental pulp tissue, as well as the entire process of dental pulp tissue’s immune defense against LPS invasion and self-repair. It is suitable for clinical research on the pathogenesis and drug treatment of human pulpitis.