HEMORRHAGIC SHOCK-INDUCED CHANGES IN THE CATHEPSIN-D ACTIVITY IN THE INTESTINAL WALL AND BLOOD-SERUM IN RATS

Hemorrhagic shock causes release of lysosomal proteolytic enzymes whic h contribute to intestinal wall destruction and can be moved into the circulation as well as into the gut lumen. The aim of the study was to examine the activity of cathepsin D in relation to the intestinal wal l injury after 60 minutes of untreated hemorrhagic shock in rats. The total cathepsin D activity was investigated in duodenum, jejunum, ileu m, cecum and colon, as well as in systemic and mesenteric blood serum, and the biochemical results were compared with morphological changes in the respective segments including immunohistochemical expression of cathepsin D. We found an increase in cathepsin D activity in duodenum and significant decrease in other parts of the gut in shocked rats. T he enzyme activity increased also in blood serum, especially systemic (p < 0.05) and insignificantly in mesenteric blood. However, sham-oper ated animals (one-side carotid artery occlusion) revealed a significan t increase In cathepsin D activity measured in mesenteric blood. The s hock resulted in lowering protein concentration in the intestinal wall and its increase in mesenteric blood. The contents of peptides and am ino nitrogen, as potential proteolytic reaction products, changed in d ifferent ways in various segments of intestine. Morphologically, the m ost intensive destruction was observed in ileum, duodenum and jejunum. Lifting of epithelial layer from lamina propria was the most frequent ly observed lesion of the intestinal wall after 60 minutes of shock. M ore advanced lesions, such as denuded mucosa with disintegration of la mina propria, occurred rarely and were not observed in colon and rectu m. By means of polyclonal antibodies against cathepsin D, we found tha t the strong expression of this enzyme was in epithelial layer - the p art of intestinal wall which was partially detached into gut lumen due to hemorrhagic shock. The changes of cathepsin D activity after 60 mi nutes of hemorrhagic shock were correlated with signs of morphological damage to the intestinal wall. Cathepsin D liberation in the intestin al wall during shock indicates the lysosomal membranes impairment and can confirm involvement of proteases in the damage to the intestinal t issue. We conclude that liberation of intestinal cathepsin D is an ear ly phenomenon during hemorrhagic shock which may contribute to the loc al wall disintegration and activation of systemic inflammatory respons e.