NEW ASPECTS IN A MURINE MODEL FOR EXTRAHEPATIC BILIARY ATRESIA

The cause of extrahepatic biliary atresia (EHBA) remains unknown, and even an animal model is still lacking. Observations in a murine infect ious model (newborn Balb/c mice infected with rhesus rotavirus group A [RRV]) reported extrahepatic biliary obstruction similar to findings in children who have EHBA. In the present study, this animal experimen t was repeated, and the clinical and histomorphologic changes were obs erved over 3 weeks. Eighty-nine newborn mice were infected with RRV, a nd 67% showed signs of cholestasis and delayed growth. Eight of these animals recovered spontaneously whereas the others remained icteric. F ourty-six pups were prepared for microscopic examination following a 2 -day interval. From the fifth day, the whole biliary tract showed edem atous swelling with cellular infiltration. Ten days later, in the extr ahepatic bile duct, a transformation took place in which concentric in filtration led to complete obstruction, sometimes with prestenotic dil atation. The intrahepatic changes showed reactive necrosis and prolife ration of the small bile ducts. In one 19-day-old mouse, a ballooning dilatation was observed, similar to a developing choledochal cyst. Inf ection with RRV induces in newborn Balb/c mice a cholestatic clinical picture with different courses of the disease leading mostly to comple te biliary obstruction and secondary hepatic changes similar to EHBA i n children. This is the first animal model for EHBA with complete obst ruction of the extrahepatic bile duct induced by infection. These find ings present a new basis for further studies. Copyright (C) 1997 by W. B. Saunders Company.