INCREASE IN SPLEEN VOLUME OF RATS ON EXPERIMENTAL MODEL OF PRE-HEPATIC PORTAL HYPERTENSION Aumento do volume do baço em modelo experimental de hipertensão portal pré-hepática em ratos

Portal system. Splenomegaly. Models, animal. ABSTRACT- Background: Pressure increase in the portal venous system, caused by reduction of blood supply to the liver, develops collateral circulation of splanchnic vessel that reaches the venous system of superior vena cava. The spleen works as an auxiliary capacitance system which compensates the increase in portal pressure that may cause splenomegaly. Aim: To reproduce experimental model of pre-hepatic portal hypertension by reducing the caliber of the vein, allowing the study of alterations in the rat’s spleen in this situation. Methods: Fifteen Wistar rats were divided into three groups of five. All animals were operated, being the first five used as control (group 1) and reoperated after 15 days (sham-operated), along with five other animals had portal hypertension induced (group 2). The last five animals, also with portal hypertension were reoperated after 30 days (group 3). Prehepatic portal hypertension was caused in experimental animals by partial ligation of portal vein in hepatic hilum. The spleen was measured during the first and second operations, allowing the calculation of its volume in the three groups studied using specifi