[Changes in membrane enzymes in warm liver ischemia]

The aim of the study is to perform a morphological analysis of certain membrane enzymes and parenchymal alterations during warm ischemia in the pig liver.

Standard hepatectomies were performed in a set of 24 pigs. Intraoperative intravenous (portal vein) hydroxyl radical scavenger Stobadine and Pentoxifylline was administered. Tissue specimens were removed from the margo acutum in interval 10, 60, 80 et 100 minutes. Applied methods of morphological analysis were concentrated on studying the activity of enzymes, which are regarded as cell membrane condition markers. First of them was the alkaline phosphatase, the second studied enzyme was the 5'-mononucleotidase. Detected findings in control group were compared to other two groups. We evaluated each sample using Image Forge Version 1.1 software (PROVER LTD., Bratislava). Applying this software we measured percentage of pre-measured activity levels of both enzymes.

In normal pig liver, the activity of alkaline phosphatase was regularly distributed in sinusoid walls in the whole lobule. At 10 minutes after the beginning of the warm ischemia, we have found focal losses of enzyme activity, especially in cells of zone 3 of the liver lobuli. One hour after the beginning of warm ischemia were the local losses of enzyme activity even more pronounced. Decreased bile canalicular 5'-mononucleotidase activity reflects cell damage, especially in pericentral areas after 60 min.of ischemia and a further decrease in activity at all surfaces of the membrane. Total amount of enzyme activity is different.

Morhological findings of enzyme activities showed that zone 2 and 3 of the liver lobule are essential for the organ survival. The study showed, that intravenous administration of Pentoxifylline and Stobadine probably protects the liver from warm ischemia injury.