A canine portal hypertension model induced by intra-portal administration of Sephadex microsphere.

Background And Aim: Big animal models of portal hypertension are important for the research into this disease. The aim of this study was to establish a canine portal hypertension model by intra-portal administration of microspheres.

Methods: Sixteen mongrel dogs were assigned to control group and experimental group randomly. The catheterization of portal vein was performed by laparotomy and the outer end of the catheter was fixed subcutaneously in the abdominal wall. The dogs of the experimental group were given intra-portal injections of microspheres at a five-day interval, six times in total. Portal hemodynamics, blood cell counting, liver and renal function test, portography, gastroscopy, liver, spleen and lung histological examination were taken to evaluate the model.

Results: 1, 2, 3 and 4 months after initial injection of microspheres, portal venous pressure rose from baseline 8.7 +/- 0.7 mmHg to 24.3 +/- 1.6, 20.6 +/- 2.1, 19.0 +/- 1.8 and 17.7 +/- 2.0 mmHg, respectively (P < 0.01). The diameter of portal vein increased from 7.6 +/- 0.3 to 8.6 +/- 0.3 mm, calculated portal resistance increased from 0.46 +/- 0.06 to 1.06 +/- 0.20 (mmHg/mL/min/kg body weight); velocity of portal blood flow decreased from 35.1 +/- 1.7 to 26.1 +/- 2.4 cm/s (P < 0.01, respectively). The animals of experimental group developed marked splenomegaly and profuse portosystemic collateral circulations with normal liver and renal function.

Conclusion: Repeated intra-portal administration of microspheres can induce stable and reproducible chronic portal hypertension in dogs with normal liver and renal functions. This model can meet multiple demands of both basic and clinical research of portal hypertension.