Study of aerobic granulocyte functional activity in the presence of a radiosensitizer [metronidazole]

The in vitro effects of metronidazole on the production of reactive oxygen species by polymorphonuclear [PMN] cells were studied by means of nitroblue tetrazolium and luminol-dependent chemiluminescence. At therapeutic doses of metronidazole [4.98-24.86 microg/mL] significant inhibition of the production of reactive oxygen species was noted in both methods. The inhibitory effect was in a dose-dependent pattern. The data suggest a scavenging mechanism of metronidazole on reactive oxygen species generated by PMN

Inhibition of luminol-dependent chemiluminescence of human granulocytes by low doses of inorganic mercury

HgCl2, added in vitro to human granulocytes in whole blood, caused a marked inhibitory effect on the luminol-dependent chemiluminescence induced by BaS04 crystals in suspension of these cells. The effect was both dose- and time-dependent when BaS04 was used to stimulate the oxidative burst in granulocytes. Incubation with the highest concentration of HgCl2 used [10 mmol/L], however, did not cause disruption of the membranes of granulocytes. The effect of HgCl2 on the granulocytes was irreversible following washing of the HgCl2-treated cells with phosphate buffered saline. HgCl2 did not affect chemiluminescence produced when luminol was excited by oxidative hydrogen peroxide in a cell-free medium. These results suggest that some of the toxicity of HgCl2 may be greater than mediated by an action on the phagocytic immune system