Induction of experimental splenomegaly with portal hypertension in rats with liver cirrhosis

Liver cirrhosis was induced in rats by administrating thioacetamide (TAA), and portal hypertension was maintained for at most 35 weeks to study the influence of portal hypertension on the weight of spleen and splenic tissues. TAA was intraperitoneally injected at dose of 200 mg/kg three times a week. The portal pressure was elevated and the weight of the spleen increased with the progression of hepatic fibrosis due to TAA. Liver cirrhosis was obviously observed after TAA was administered 60 times. The maximum ratio of the weight of the spleen to body weight in the group administered TAA was higher by 4.08 times than that in the control group. In all 49 rats used in the experiment there was a high correlation (r=0.930, p<0.01) between the portal pressure and the ratio of spleen to body weight. Histological observation revealed that the red pulp tended to be enlarged, while the white pulp tended to be reduced, with increases in portal pressure and weight of the spleen. It also histologically revealed an increase in the splenic sinus-like structure, narrowing of the splenic cords, fibrosis due to reticular cell proliferation in the red pulp and fibrosis around the central artery in the white pulp. These histological changes in rats were similar to the histological findings of splenomegaly accompanying portal hypertension in humans. This suggests that the animal model prepared in the present experiment is useful as a model of splenomegaly due to portal hypertension.