MyD88 knockout (MyD88?/?) and wild-type (WT) BALB/c pups were injected with Rhesus rotavirus or saline on day 1 of life. The mice were monitored for clinical symptoms of BA, including jaundice, acholic stools, bilirubinuria, and death. The liver and extrahepatic bile ducts were harvested for histologic evaluation and the quantification of viral content, determination of cytokine expression, and detection of inflammatory cells.
Rhesus rotavirus infection produced symptoms in 100 % of both MyD88?/? and WT pups, with survival of 18 % of WT and 0 % of MyD88?/? mice. Histologic analysis demonstrated bile duct obstruction in both MyD88?/? and WT mice. Viral titers obtained 7?d after infection and expression of interferon-¦Ã and tumor necrosis factor-¦Á at day 3, 5, 8, and 12?after infection revealed no significant differences between the WT and MyD88?/? mice. Flow cytometry demonstrated similar levels of activated CD8+ T cells and natural killer?cells.
The pathogenesis of murine BA is independent of the MyD88 signaling inflammatory pathway, suggesting alternative mechanisms are crucial in the induction of the model.