Evaluation of hepatocyte injury following partial ligation of the left portal vein

Background/Aims: Total ligation of the left portal vein is thought to induc e both hepatocyte apoptosis and necrosis, The pathological impact of partia l ligation of a branch of the portal vein has not yet been evaluated. Methods: We studied the degree of hepatocyte injury following 0, 43, 48, 59 , 68, 72, 78 and 100% left portal vein stenosis in 200-g Sprague-Dawley mal e rats. Serum alanine aminotransferase levels, total body weight, and left and right liver lobe weights were measured at 2 and 7 days. Mitosis and H-3 -thymidine labelling indices were measured as markers of proliferation; the apoptotic index and TUNEL stain were used as markers to measure apoptotic cell death. Necrosis was assessed morphologically, All these parameters wer e evaluated 2 days after ligation, Results: There was a direct relation between the increase in weight of the right lobes and the reduction in weight of the left lobes, The degree of we ight change correlated significantly with the degree of stenosis, In the ri ght lobes, mitosis and H-3-thymidine labelling were increased in proportion to the degree of stenosis, In the left lobes, the decrease in volume of he patocytes correlated with the degree of ligation, especially in the pericen tral areas. Necrosis was identified only when ligation was greater than or equal to 68%, this being associated with an increase in alanine aminotransf erase levels. On the other hand, apoptotic cells were identified in increas ing numbers, starting from the lowest degree of ligation to 100% ligation, This was found both morphologically and with TUNEL stain. Conclusions: Partial ligation of the left portal vein induces left liver at rophy through hepatocyte volume loss and apoptosis, Necrosis is found only when the degree of ligation is severe.