动物造模,药效评价,肝炎病毒 z-bio 2024-08-02 314

　　At present, animal models of hepatitis B virus mainly include tree shrew hepatitis B model, duck hepatitis B model, marmot hepatitis B model, and mouse hepatitis B model.

　　【 Modeling Mechanism 】 Hepatitis B virus (HBV) is mainly transmitted through blood and blood products. It is injected into animals through intravenous injection or hydrodynamic high-pressure injection using HBV patient serum or HBV DNA.

　　[Method of Modeling]

　　Tree shrews: 0.5 ml of serum of hepatitis B B virus surface antigen (HBsAg) and hepatitis B B virus e antigen (HBeAg) positive patients with hepatitis B B were inoculated into tree shrews via femoral vein.

　　Duck: Duck hepatitis B virus (DHBV) is injected into the body of ducks through intravenous injection, intramuscular injection, intraperitoneal injection, hepatic injection, and duck embryo intravenous injection.

　　Woodchuck: Woodchuck hepatitis virus (WHY) is another hepatotropic DNA virus discovered after human HBV. Chronic infection with WHV in marmots can gradually develop into severe hepatitis and liver cancer, which is very similar to the development process of human HBV infection. Vaccinating young marmots with WHV can establish a model of marmot hepatitis.

　　Transfection of mouse model using hydrodynamic method: HBV plasmid DNA was injected into the tail vein of mice using high-pressure hydrodynamic method, and HBV DNA was detected in the serum after injection.

　　[Model Features]

　　Tree shrews: After being infected with HBV, HBsAg, anti HBs, or HBV DNA can be detected in the blood; Immunohistochemical detection of liver tissue shows HBsAg and/or HBcAg; Elevated serum ALT; Southern blotting can detect the presence of integrated forms of HBV DNA in liver tissue. The tree shrew model has low cost, easy experimental operation, and is not strictly limited by animal ethics.

　　Ducks: The infection rate of 1-day-old ducks vaccinated with DHBV can approach 100%, and they can maintain a long period of viremia. DHBV DNA can also be detected in the liver. After vaccination at 5 days of age, DHBV DNA and endogenous DNA polymerase activity decreased, while viremia did not occur after vaccination at 14 days of age. After infection with the virus, the body can simultaneously exhibit corresponding virus specific humoral and cellular immune responses, producing duck DHBsA9. And it can last for 22 weeks.

　　In 1996, Walter et al. reported that tree shrews vaccinated with human HBV during their neonatal period had outcomes similar to acute self limiting hepatitis in humans, while vaccination in adulthood resulted in transient infection. Vaccination with HBV during childhood and perinatal period can improve infection efficiency. Newly born tree shrews can be inoculated with human HBV, and the virus can exist in the animal's body for a long time and replicate stably. In 2012, the co receptor of hepatitis B B virus and hepatitis D virus - sodium ion taurocholic acid co transport polypeptide was found in the primary hepatocytes of tree shrews, so tree shrews are expected to become a reliable animal model of human HBV.

　　The viremia of ducks infected with DHBV is correlated with their age, and the timing of DHBV infection is an important factor affecting the infection rate and prognosis. After intraperitoneal injection of DHBV infection into 1-day-old ducks, the positive rate was about 89% after 2 weeks, and reached about 94% after 4 weeks, lasting for 22 weeks. After infection at 10 days of age, the positive rate is only about 16% after 2 weeks, about 38% after 4 weeks, and can reach 61.1% after 6 weeks. After 12 weeks, about 1/2 of DHBV positive ducks show DHBsA9 and DHBV DNA turning negative. The duck model has a high DHBV infection rate and is easy to feed, making it a good model for evaluating the efficacy of antiviral drug treatment in preclinical settings. However, there are significant structural differences between DHBV avian hepatotropic virus and human HBV, and ducks have significant evolutionary differences from humans, so the process of human HBV infection cannot be well reproduced.

　　WHV infection in newborn marmots often presents as chronic infection, which can be used to study the chronicity mechanism of HBV, for the development of HBV vaccines and antiviral drugs, and for related research on HBV life cycle, molecular mechanism, infection and carcinogenesis mechanism. However, the marmot hepatitis virus animal model cannot directly infect HBV, and there are still certain differences between WHV and HBV, which cannot fully simulate the pathological process of HBV.

　　Hydrodynamic transfection mouse model: This model can be used to study the life history and chronic infection mechanism of HBV, and can specifically locate mutated HBV-DNA to investigate the mechanism of single or multiple genes in the process of HBV infection; Meanwhile, as an immune totipotent mouse, it can be used to study the mechanism of immune effects caused by viruses.

　　Otter: After infection with WHV, WHsAg antigenemia occurs, and characteristic WHV surface and core particles can be seen under electron microscopy.

　　Hydrodynamic transfection of mouse model: After infection with HBV, the virus titer is high, HbsAg can be maintained in vivo for more than 6 months, and HBV replication transcription intermediates can be continuously detected in vivo for up to 1 year.