The role of reovirus type 3 infection in an established murine model for biliary atresia.

AIM OF THE STUDY: Infection of newborn Balb/c-mice with Rhesus rotavirus (RRV) leads to cholestasis and biliary atresia. In this current model, Reovirus Type 3 was investigated to ascertain whether Reovirus Type 3 causes the same or similar hepatobiliary lesions as RRV. METHODS: Newborn Balb/c-mice were infected with Reovirus Type 3 Dearing and Reovirus Type 3 Abney on the first day of life. Clinical observation followed for a period of at least 10 days. Cholestatic and/or dystrophic mice were prepared and specimens were taken for histological examination. RESULTS: Infection with RRV showed a 85 % morbidity for biliary atresia as described before. Clinical disease, following an infection with Reovirus T3 Dearing, showed neurological symptoms such as ataxia, and all mice died within 3 weeks. No obstructive or atretic changes of the hepatobiliary ducts could be seen either macroscopically or histomorphologically. 60 % of the mice having been infected with Reovirus T3 Abney showed signs of cholestasis and oily fur syndrome, but almost 15 % recovered from the disease. Although the histological findings did not reveal biliary atresia, inflammation and destruction of bile ducts could be observed. CONCLUSION: In comparison to the RRV infection in a Balb/c-mice model, where biliary atresia could be induced, infection with Reovirus T3 in this model did not lead to biliary atresia. But Reovirus T3 Abney infection revealed inflammatory signs as described in the literature before. The question as to why different hepatotrophic viruses lead to different changes in the murine hepatobiliary tract has to be investigated in further studies.

Immunological gap in the infectious animal model for biliary atresia.

BACKGROUND: Extrahepatic biliary atresia (EHBA), the etiology of which still remains unclear, occurs exclusively in newborns and has recently been simulated in an animal model. It is possible to trigger an EHBA corresponding to the human disease by means of intraperitoneal infection of newborn Balb/c mice with rhesus rotavirus (RRV). The aim of the present study was to determine the conditions and circumstances for inducing biliary atresia in this model focusing on first-line immunological aspects. METHODS: Newborn as well as pregnant Balb/c mice were intraperitoneally infected with RRV. RESULTS: The highest incidence of cholestasis (86%) was achieved by infection with 10(6) PFU/ml RRV within the first 12 h postpartum, resulting in EHBA with a lethality of 100%. However, the later the newborn mouse is infected, the less likelihood there is that EHBA is triggered. Additionally, the incidence of biliary atresia in this model depends on the quantity of the virus that is given intraperitoneally. However, the development of biliary atresia is not correlated to the virus in the liver. The antepartum infection of pregnant mice does not induce EHBA in the offspring. Female mice that are immunized against RRV protect their newborns from developing RRV-induced cholestasis and EHBA. This protection is transmitted transplacentally and not by breast milk. CONCLUSION: It is obvious that a temporary immunological gap is essential for virally induced EHBA. Further studies should focus on specific parameters of the immune system of newborn mice in this biliary atresia model.