动物造模,肺炎链球菌肺炎模型 z-bio 2023-09-26 894

　　In the ranking of mortality rates for human diseases, bacterial pneumonia and influenza rank sixth. Animal models can be used to study the mechanism of the interaction between influenza and pneumococcus.

　　1. Mouse pneumococcal secondary infection model

　　(1) Modeling method: The strains of Streptococcus pneumoniae used were D39 (serotype 2), WU2 (serotype 3), and TIGR4 (serotype 4). H1N1 mouse adaptation strain influenza A/Puerto Rico/8/34 (PR8) with 400 pfu inhalation infection in the mouse oropharynx (soluble in 50 μ PBS). After 6 days of virus infection, the infection is then inhaled through the mouth and throat × D39 and 5 for 100 000 cfu × 100 000cfu Pspa -, Hyl or NanA - mutant 50 μ After 24 hours of pneumococcal infection with PBS, the mice were euthanized and lung tissue was lavaged with 5ml. The lung tissue was taken out and homogenized in the lavage solution, and frozen at -80 ℃. Detect the bacterial count in lung homogenate.

　　(2) Result: Before being inoculated with bacteria, the mice showed symptoms of influenza virus infection, such as arched back, erect hair, and mental fatigue. After 7 days of influenza virus inoculation, the titer of influenza virus in the lungs of mice ranged from 10 to 10 to the 7th power pfu. The bacterial count in lung tissue of mice pre infected with influenza virus is much higher than that of non infected individuals (15000 to 29000 times). The reinfection of pneumococcus after 6 days of influenza virus infection can serve as a model for secondary infection of pneumococcus after influenza, used to study the mechanism of the interaction between influenza and pneumococcus in pathogenesis.

　　2. The ferret model

　　(1) Model production: 1 × Influenza virus with EID50 to the 6th power of 10 and 1 × Dilute pneumococcal bacteria to the 6th power of 10 with sterile PBS, with a volume of 1ml (500 μ L/nostril), ferrets were anesthetized with 3.5% isoflurane inhalation and infected through nasal drops. The ferret was infected with influenza virus or PBS control, and after 5 days, it was infected with pneumococcal strain D39 or infused with PBS. Animals are divided into three groups: influenza virus, pneumococcus, or infected with influenza virus first and then pneumococcus, with two animals in each group. Observe clinical symptoms and collect blood samples and nasal lavage fluid at 0, 6, 24, 36, and 48 hours. When collecting nasal flushing solution, 1ml PBS was injected into the ferret's nasal cavity (60mg ketamine intramuscular injection anesthesia) and recycled. Titrate the influenza virus in nasal lavage with MDCK cells, count the pneumococcal colonies, and culture on a soybean trypsin agar plate with 3% (vol/vol) sheep red blood cells. After 48 hours of pneumococcal infection, the ferret was euthanized. Remove the lungs and fix them in 10% neutral formalin. Routine production observation.

　　(2) Result: Ferrets infected with influenza showed typical symptoms such as runny nose and reduced activity, while ferrets infected only with pneumococcus did not show runny nose or other respiratory symptoms, nor did they show reduced activity. Ferrets infected with pneumococcal bacteria after the outbreak of influenza virus exhibit a more severe disease state compared to individuals infected alone