AIM: To study the stability of portal hypertension (PHT) caused by partial ligation of the portal vein ligation (PVL) in a rat model. METHODS: Thirty male adult Wistar rats were divided into two groups: 10 in Group I received a sham operation; and 20 in Group II received partial PVL. Portal vein pressure (PVP) was measured at four time periods: before ligation, 2 wk, 6 wk and 10 wk post-surgery. Portal venography, blood sampling and liver and spleen pathological examinations were conducted at 10 wk after surgery. RESULTS: The PVP was 9.15 +/- 0.58 cmH(2)O before ligation, and increased to 17.32 +/- 0.63 cmH(2)O 2 wk after PVL. By repeat measurement of the PVP in each rat, it was shown to remain elevated for 10 wk. There were no significant differences in the pressure measurements at 2 wk, 6 wk and 10 wk. Varices were found mainly in the mesenteric vein 2 wk after PVL, which were more obvious later, while these manifestations were similar at week 6 and week 10. Portal venography demonstrated the varices and collaterals. There was no significant change in liver pathology. The volume of the spleen was enlarged 2-fold after ligation, and the sinus of the spleen was enlarged due to congestion. Significant sinus endothelial cell proliferation was observed, but no evidence of hypersplenia was found on hemogram and biochemical examination. CONCLUSION: These findings suggest that a satisfactory prehepatic PHT rat model can be obtained by partial ligation of the portal vein, and this PHT rat model was stable for at least 10 wk. (C) 2009 The WJG Press and Baishideng. All rights reserved.