THE INFLUENCE OF INTESTINAL ISCHEMIA AND REPERFUSION ON BIDIRECTIONALINTESTINAL BARRIER PERMEABILITY, CELLULAR MEMBRANE INTEGRITY, PROTEINASE-INHIBITORS, AND CELL-DEATH IN RATS

Intestinal ischemia and reperfusion injury (I/R) is probably involved in the pathogenesis of intestinal barrier dysfunction, associated with the concomitant translocation of enteric bacteria and toxins and the potential development of multiple organ failure. The intestinal endoth elial and epithelial layers play a major role preventing the entry of toxic substances from the gut, but the influence of protease-antiprote ase systemic balance on these barrier functions and the relationship b etween epithelial DNA synthesis, apoptosis, and endothelial and epithe lial barrier macromolecule permeability are not fully investigated. En dothelial and epithelial barrier macromolecular permeability, epitheli al DNA synthesis, the endothelial and epithelial plasma membrane syste m, apoptosis and oncosis, plasma levels of proteinase inhibitors, and proenzymes were measured in rats subjected to 20 and 40 min intestinal ischemia and 1, 3, 6, or 12 h reperfusion. Endothelial permeability i ncreased after both 20 and 40 min intestinal ischemia, Epithelial perm eability significantly increased during 1-6 h reperfusion after 20 min ischemia and during 1-12 h reperfusion after 40 min ischemia. Epithel ial DNA synthesis increased in animals with 20 min ischemia followed b y 12 h reperfusion. Plasma levels of prekallikrein, C1-esterase inhibi tor, and alpha 1-macroglobulin were significantly lower following both 20 and 40 min ischemia from 3 h reperfusion and on. Apoptotic epithel ial cells significantly increased in animals subjected to 20 min ische mia followed by 12 h reperfusion. The severity of reperfusion injury i n the intestinal endothelial and epithelial barrier seems to correlate with the period of ischemia and the pathway of cell damage and death, together with proteinase-antiproteinase imbalance.