Ascorbic acid inhibits polymorphonuclear leukocytes influx to the place of inflammation--possible protection of lung from phagocyte-mediated injury.

Abstract

Ascorbic acid as a scavenger of oxidants derived from human polymorphonuclear leukocytes (PMNL) may have clinical significance in antioxidant prevention of emphysema. However, there is a risk relevant to its administration because this drug was reported to enhance PMNL chemotactic response and thus could create protease burden in the lower airways. In this study we have investigated the effect of ascorbic acid on the PMNL influx to the place of inflammation developed in the mouse pleural cavity after injection of zymosan-activated serum (ZAS). We also evaluated the influence of ascorbic acid on human PMNL spontaneous migration, chemotaxis to ZAS and n-formyl-methionyl-leucyl-phenylalanine (FMLP) under agarose. The previous ascorbic acid intraperitoneal administration (single dose 10 mg per day for 3 following days) inhibited leukocyte influx. Total number of cells found in the cavity, number of PMNL and lymphocytes was 2.4, 3.5, 1.7-fold lower than in animals without ascorbic acid, respectively. In vitro ascorbic acid (concentrations of 1 to 10 mg/dl) enhanced PMNL spontaneous migration, concentrations 10 mg/dl and higher inhibited PMNL chemotaxis to ZAS and had no influence on migration of the cells toward FMLP. These results suggest that ascorbic acid may be useful for prevention of lung oxidant injury not only as oxidant scavenger but also as an inhibitor of PMNL influx to the pulmonary tissue.