A new experimental animal model of portal hypertension. Intrahepatic portal obstruction by injecting DEAE-cross-linked dextran microspheres into the portal vein in the rabbit.

We proposed a new experimental animal model for portal hypertension in the female Japanese white rabbit by an intraportal injection of DEAE-cross-linked dextran microspheres (100 +/- 25 microns in diameter). Histology of the liver revealed portal obstruction by the injected microspheres in almost all portal triads, resulting in a foreign body granuloma. A sustained elevation of the portal pressure by a mean of 36.7% as compared with the basal value was observed for at least eight weeks in association with the portal-systemic collateral circulation demonstrated by portography, the radioisotope labeled microsphere method and histological examination of the esophagus and the liver. The elevation in portal pressure in the eighth week was associated with an increase in the portal blood flow determined at the main portal trunk. This was in accordance with the forward theory of the pathogenesis of portal hypertension. Since this model appears to show the two main conditions characteristic of portal hypertension persistent elevation of portal pressure and both extra- and intrahepatic portal collaterals, mimicking those in humans, portal obstruction by injecting DEAE-cross-linked dextran microspheres into the portal vein of the rabbit could provide a versatile model for portal hypertension.