Abstract
The auther studied a role of leukocyte-elastase in vascular endothelial cell injury induced by activated leukocytes. Using an interactive laser cytometer with ACAS 570, the intracellular peroxide level was determined in dichlorofluoresein-diacetate (DCFDA) prelabeled vascular endothelial cells. Addition of elastase (5 μg/ml) to the monolayer of the prelabeled endothelial cells induced an increase in fluorescence intensity in cells. The increase in fluorescence was inhibited by such protease inhibitors as α-1 antitry-psin and α-2 macroglobulin. Moreover, pretreatment of the endothelial cells with allopurinol, xanthine oxidase inhibitor, abolished the increase in the fluorescence of the DCFDA prelabeled endothelial cells exposed to elastase.
These data suggest that the activity of leukocyte elastase is related to the production of peroxide in endothelial cells. Elastase may activate xanthine oxidase or increase the conversion of xanthine dehydrogenase to xanthine oxidase, and it may be deeply involved in vascular endothelial cell injury elicited by activated leukocytes.
