EXPERIMENTAL EXTRAHEPATIC OBSTRUCTION OF PORTAL-VEIN - DOCUMENTATION OF HISTOPATHOLOGICAL ALTERATIONS IN LIVER AND EXTRAHEPATIC TISSUES

The histopathology of the portal vein in human extrahepatic portal vei n obstruction (EHPVO) in the form of cavernomatous transformation of t he portal vein is well documented. However, a similar detailed histopa thology has not been documented in experimental EHPVO, even though the model has been in existence for many years. An experimental model of EHPVO was created by partial ligation of the portal vein in 20 rats. A control group of 11 sham operated (SO) rats was also studied. Develop ment of portal hypertension was confirmed by measurement of intrasplen ic pulp pressure (19.7 + 7.1 cm normal saline vs 12.9 + 1.1 cm of norm al saline in SO rats). Histopathological evidence included varices in the oesophagus and congestion in the submucosa and mucosa of the stoma ch and capillarization of sinusoids in the spleen. Animals were killed at 22-265 days post-ligation. While SO animals showed mild focal sinu soidal congestion and a normal portal vein, the experimental group of animals with EHPVO showed oedema around the portal vein, multiple dila ted vascular channels near the hilum resembling cavernomatous transfor mation and severe sinusoidal congestion. Jejunum and kidneys showed co ngested veins in the experimental group. None of the SO animals showed this change. Thus, experimental EHPVO does reproduce some histologica l changes observed in human EHPVO.