Effect of extra-hepatic portal venous obstruction upon the levels of anticoagulant factors in rabbits

Objective To explore the effect of extrahepatic portal venous obstruction upon the levels of protein C, protein S and antithrombin Ⅲ in rabbits. Methods From March 2016 to December 2016, 25 New Zealand white rabbits were used for modeling of extrahepatic portal hypertension by partial ligation of extrahepatic portal vein.The mean weight was 2.9 (2.2-3.4) kg.And another 10 rabbits were used as control group.The portal pressure and size of spleen were measured pre- and post-operatively at 4 weeks.The blood samples were collected at 4 weeks for detecting the serum levels of protein C, protein S and antithrombin Ⅲ by enzyme-linked immunosorbent assay (ELISA). And the levels of protein C, protein S and antithrombin Ⅲ were compared between two groups. Results Seventeen animal models of extrahepatic portal hypertension were established successfully and eight animals died from wound infection or bleeding due to portal hypertension.Portal pressure increased significantly from preoperative (10.6±2.6) cmH2O to postoperative (25.1±7.2) cmH2O (P<0.01). The size of spleen increased significantly after 4 weeks [length: (6.0±0.8) vs.(5.3±0.5) cm, P=0.045; width: (1.2±0.3) vs.(1.0±0.2) cm, P=0.002]. The levels of protein C and antithrombin Ⅲ in model group were significantly lower than those in control group [PC: (21.1±2.7) vs.(32.7±4.0) μg/ml, P=0.015; ATⅢ: (25.5±5.5) vs.(38.6±4.3) μg/ml, P=0.031]. No significant inter-group difference existed in the level of protein S. Conclusions The deficiency of protein C and antithrombin Ⅲ is caused by reduced hepatopetal blood flow due to extrahepatic portal venous obstruction. Key words: Hypertension, portal; Models, animal; antithrombin Ⅲ