Inhibition by reactive aldehydes of superoxide anion radical production from stimulated polymorphonuclear leukocytes and pulmonary alveolar macrophages. Effects on cellular sulfhydryl groups and NADPH oxidase activity.

Alpha,beta-unsaturated aldehydes such as acrolein (ACR) and crotonaldehyde (CRO) have been shown previously in our laboratory to inhibit the production of superoxide anion radical (O2-) by stimulated phagocytic cells in vitro in a dose-related manner. Based on the known reactivity of these compounds towards cellular sulfhydryls (SH), the present studies were aimed at investigating cellular SH status in relation to O2- production. Plasma membrane surface SH groups were measured using carboxypyridinedisulfide and monitoring the resultant formation of mixed disulfides through assay of thione released into the supernatant fraction. Intracellular non-protein sulfhydryls were measured using 5,5'-dithiobis-2-nitrobenzoic acid. In both human polymorphonuclear leukocytes (PMN) and rat pulmonary alveolar macrophages (PAM) there was a dose-related decrease in surface SH and soluble SH after ACR and CRO treatment. Propionaldehyde, a three-carbon saturated aldehyde, was without effect. The decrease in surface SH was greater than the decrease in soluble SH. In addition, in PMN and PAM preincubated with 5-40 microM ACR, there was a dose-related inhibition in the rate of O2- production with no effect on the lag time as measured by cytochrome c reduction. In stimulated PMN, there was a dose-related decrease in the rate after addition of 5-40 microM ACR. These data suggest that changes in SH status by reactive aldehydes can modulate the activity of the plasma membrane NADPH oxidase responsible for O2- production.