动物造模,药效评价,甲型肝炎 z-bio 2024-07-30 410

　　[Operation steps] Take the stool of a hepatitis A patient with positive hepatitis A antigen, prepare a 5% suspension, and centrifuge at 3000 and 8000 rpm for 30 minutes respectively. The supernatant is frozen at -80 ℃ for later use. Adult healthy tree shrews were orally administered with 0.5ml of fresh stool suspension containing 5% hepatitis A antigen positive samples from patients with hepatitis A in the ABSL-3 laboratory. After infection, detoxification continues for 15-21 days with a titer of 1:10-1:320. After 30 days, detoxification stops. Administer 1ml of a 10% suspension of the first generation infected tree shrew's hepatitis A antigen positive feces orally to each normal tree shrew for second-generation infection; Antigen can still be detected in the feces about one week after infection, and detoxification lasts for 12-27 days, with a peak at 7-13 days; Prepare a 10% suspension from the feces of second-generation infected animals during the peak period of detoxification, and perform third-generation infection using the same method. Antigens can also be detected in the feces of the latter.

　　【 Result Analysis 】 (1) Hepatitis A virus can reproduce in tree shrews, and detoxification from feces begins 7-13 days after infection; Lasting for 15-21 days, as the virus passes through the tree shrew's body, the incubation period seems to shorten and the infection rate tends to increase; However, most animals are non clinical, and only a few first generation infected animals have transient elevation of serum alanine aminotransferase (SGPT), which seems to be related to the adaptability of the virus. (2) After 2-16 weeks of infection, 78% of animals showed hepatitis A virus antibodies in their serum, but their titers were low and some could not be reproduced quickly. In the control group, animals continuously tested high titers of hepatitis A virus antibodies before and after taking normal human fecal filtrate, which may be caused by natural infection, as tree shrews have a habit of eating human feces. (3) The size, shape, and immunological properties of virus particles were observed using solid-phase radioimmunoassay and immunoelectron microscopy, which confirmed that the antigen extracted from infected tree shrew feces was similar to human hepatitis A virus. (4) Autopsy of infected tree shrews revealed liver congestion, edema, and parenchymal degeneration; However, compared with the use of hepatitis A virus to infect marmosets, chimpanzees, and red faced monkeys both domestically and internationally, tree shrews have milder liver lesions and do not exhibit typical changes of acute hepatitis. This may be related to the amount and virulence of the virus infection and its degree of reproduction in tree shrews.