动物造模,药效评价 z-bio 2024-08-22 522

　　(1) The replication method involves intraperitoneal injection of pentobarbital sodium at a dose of 30mg/kg body weight in approximately 4-month-old SD rats. The animal is fixed in a supine position on the surgical plate. After routine disinfection and hair removal, a longitudinal 1cm incision is made at a distance of 3cm below the lip on the neck to expose the neck muscles and separate the trachea longitudinally; Select a 2mm transverse incision in the wider tracheal cartilage gap beneath the cricoid cartilage; Use a No. 6 venous catheter for tracheal intubation, slowly extend it to about 3cm below the sternum angle, and wait for a tactile sensation to appear, which is the right lung lobe. Quickly inject 0.02ml of Pseudomonas aeruginosa (isolated from sputum of clinical bronchiectasis patients) with a concentration of 1000000000000 CFU/L and 1ml of air into the catheter using a microsampler, then quickly remove the catheter and erect the fixation plate to maintain the vertical position of the rat to alleviate respiratory disorders. After the rat's breathing stabilizes, the tracheal incision is sutured longitudinally, and the neck muscles and skin are sutured horizontally in two layers. After surgery, the model rats were intraperitoneally injected with 10000 U of penicillin G and 10ml of 50% glucose solution by gavage every day for 3 consecutive days. On the 14th day after modeling, the rats were euthanized, and their tracheal, bronchial, and lung tissue specimens were fixed with fixative solution, and routine tissue sections were made for pathological observation under light microscopy.

　　(2) The model features: Upon visual observation, the bronchi in the top and bottom lobes of the model rats exhibit columnar, cystic, and spherical dilation, with purulent secretions filling the lumen and even completely blocking it. Patchy yellow consolidation can be seen in both the top and bottom lobes, and the settling test is positive. Under microscopic histopathological observation, varying degrees of damage and rupture can be seen on the walls of the bronchial tubes in the top and bottom lobes. The columnar ciliated epithelial cells of the bronchi proliferate, and in some areas, they even show combined or budding changes. Some epithelial cells die or shed, forming ulcers or squamous metaplasia; The lumen is significantly dilated compared to the same level of bronchi, and the lumen is filled with pus cells and shed epithelial cells. A large number of inflammatory cells, mainly monocytes, pus cells, and lymphocytes, can be seen infiltrating the submucosal layer, smooth muscle layer, and peribronchial lung tissue, forming patchy lesions such as bronchitis, peribronchial inflammation, and pneumonia at the infiltration site. The submucosal layer is compressed by the dilated lumen and undergoes atrophy. Masson staining confirms smooth muscle atrophy and rupture, replaced by growing fibrous tissue. Atrophy or compensatory emphysema occurs in the surrounding lung tissue of the dilated bronchi. Pulmonary capillaries or partial bronchi accompanied by congestion or bleeding of small arteries and veins. During the modeling surgery, attention should be paid to the appropriate depth of tracheal intubation. If it is too shallow, it will divert the high-pressure oxygen source and affect the ventilation of the right lung lobe; If it is too deep, it will cause uneven pressure in the left lung lobe airway, leading to local lung rupture. In addition, the working parameters of the artificial ventilator should be adjusted according to the respiratory rate and tidal volume after anesthesia in rats to prepare for open chest surgery. When ligating lung lobes, the time for the parietal lobe to be fully exposed outside the chest cavity should not be too long, otherwise it may cause congestion and necrosis of the parietal lobe.

　　(3) Previous studies in comparative medicine have used the method of ligating the bronchi and injecting Pseudomonas aeruginosa into the bronchi to replicate a rat model of bronchiectasis. The aim is to utilize susceptible bacteria in the respiratory tract of rats and cause purulent infections in the bronchi, with purulent exudate blocking the bronchi and increasing local pressure due to ligation, leading to bronchiectasis. This modeling method highlights the main pathological factors such as bronchial infection, obstruction, and traction, which is basically consistent with the clinical process of human bronchiectasis formation. However, this method has many problems in important aspects such as open chest surgery path, artificial mechanical ventilation parameters, bronchial ligation methods, and intrabronchial injection. Even with proficient surgical skills, the success rate of surgery can only reach 50%. And this model adopts the method of directly injecting Pseudomonas aeruginosa into the bronchus, which can also cause bronchiectasis in model animals due to bronchial infection, obstruction, and traction. The pathological characteristics of the bronchi, the secretion of bronchial secretions, and the content of Pseudomonas aeruginosa in bronchial flushing fluid of the model animals are basically similar to those of human bronchiectasis lesions, but the success rate of modeling can be significantly improved. This model is applicable for research on drug therapy and drug screening for human bronchiectasis.