Effect of sulphite on the oxidative metabolism of human neutrophils: studies with lucigenin- and luminol-dependent chemiluminescence.
To assess the effect of sulphite on the oxidative metabolism of human neutrophils, chemiluminescence (CL) measurements were performed using lucigenin and luminol as chemiluminigenic probes. Lucigenin-dependent CL was used for measuring superoxide anion (O2-) production, and luminol-dependent CL was used for determination of myeloperoxidase (MPO)-connected processes. With sulphite concentrations of 0.01 to 1 mmol/L, resting neutrophils showed an up to sixfold increase of lucigenin-dependent CL, but only a 1.9-fold increase of luminol-dependent CL. Subsequent stimulation of sulphite-treated neutrophils with phorbol myristate acetate (PMA) (soluble stimulant) or zymosan (particulate stimulant) resulted in an additional significant increase of lucigenin-dependent CL compared to stimulated control cells, whereas luminol-dependent CL increased slightly by 0.01 mmol/L sulphite and decreased then continuously. Sulphite concentrations above 1 mmol/L decreased both lucigenin- and luminol-dependent CL of resting and PMA- or zymosan-stimulated neutrophils. Lucigenin-dependent CL of sulphite-treated and subsequently stimulated neutrophils was strongly inhibited by extracellularly added superoxide dismutase, whereas luminol-dependent CL was markedly reduced by the MPO inhibitor azide. The intracellular activity of MPO in neutrophils stimulated with PMA in the presence of sulphite (2 mmol/L) was reduced by 55%. Sulphite (0.1 mmol/L) also inhibited strongly the activity of MPO in a cell-free system. These results indicate that micromolar concentrations of sulphite exert a stimulating effect on the O2- production of neutrophils extracellularly, but have an inhibitory effect on MPO-catalysed reactions intracellularly.
Mishra
A
A
GSF-Forschungszentrum für Umwelt und Gesundheit, Projekt Inhalation, Neuherberg, Oberschleissheim, Germany.
Dayal
N
N
Beck-Speier
I
I
D000166:Acridines; D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D008163:Luminescent Measurements; D008165:Luminol; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D009195:Peroxidase / Q000097:blood*; D012680:Sensitivity and Specificity; D013447:Sulfites / Q000494:pharmacology*; D013481:Superoxides / Q000097:blood*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015054:Zymosan / Q000494:pharmacology
D000166:Acridines; D013447:Sulfites; D013481:Superoxides; C033472:10,10'-dimethyl-9,9'-biacridinium; D008165:Luminol; D015054:Zymosan; D009195:Peroxidase; D013755:Tetradecanoylphorbol Acetate