The Effects of Proteolytic Agent on the Lung Injured by Endotoxemia

ABSTRACT

The authors studied the lung injury induced by endotoxemia and the effects of proteolytic agent on the lung changed by endotoxemia. Sprague-Dawley rats were intraperitoneally administrated with a single dose of endotoxin (4 mg/kg, E. coli 025 B6 lipopolysaccharide) or with endotoxin and gabexate mesilate (200 mg/kg), a proteolytic agent, concomitantly. Rats of each group were scarificed at 9, 18, and 27 hours after injection. Light and electron microscopic examination were done. The results obtained were summarized as follows Light microscopic exmination revealed congested capillaries and neutrophilic infiltration in both groups. Electron microscopic findings were interstitial and alveolar neutrophilic infiltration, endothelial swelling with increased pinocytotic vesicles and cytoplasmic process formation, and interstitial edema. Decrease of osmiophilic bodies in the type II pneumocytes had appeared at 9 hours after endotoxin injection. These changes were increased in severity at 18 hours and 27 hours after endotoxin injection. In the group of concomitant treatment of gabexate mesilated and endotoxin, there was no edema at 9 hours after injection. After 18 hours welling of endothelial cell and interstitial edema had appeared. However, the severity of the edema was markedly decreased. Type II pneumocytes showed well preserved osmiophilic bodies. According to these results, it is considered that administration of gabexate mesilate can significantly redeced the lung injury induced by endotoxemia.