NEUTROPHIL-MEDIATED PHOSPHOLIPID PEROXIDATION ASSESSED BY GAS-CHROMATOGRAPHY MASS-SPECTROSCOPY

Disease pathophysiology frequently involves manifestations of the syst emic inflammatory response syndrome. Oxyradicals represent key inflamm atory mediators, and neutrophils are one important source of oxyradica ls. This investigation examined neutrophil-mediated peroxidation of di linoleoyl phosphatidylcholine (DLPC) liposomes by monitoring the appea rance of monohydroxyl linoleic acid with the use of gas chromatography -mass spectroscopy (GC-MS), compared with traditional assessment of th iobarbituric acid-reactive species (TEARS) and phosphatidylcholine-spe cific conjugated dienes. DLPC was peroxidized in a system using activa ted neutrophils in balanced salt solution containing chelated iron. 9- Monohydroxyl linoleic acid and 13-monohydroxyl linoleic acid were read ily identified in neutrophil-mediated peroxidized DLPC with the use of GC-MS. Neutrophil NADPH oxidoreductase specific activity correlated h ighly with total ion current or specific ion monitoring of integrated peak areas for peroxidized linoleic acid but correlated poorly with DL PC-derived TEARS or conjugated dienes. These results ascertain that ac tivated neutrophils mediate phosphatidylcholine lipid peroxidation to specific products, which may be precisely monitored with the use of GC -MS. The extent of this peroxidation is highly correlated with the mag nitude of the neutrophil respiratory burst.