Effects of naloxone on phagocyte functions

Introduction

Naloxone has been proposed to treat septic shock. We assessed by flow cytometry its effect in vitro on phagocytose (PH) and burst oxidation (BO) of neutrophils and monocytes after various stimuli in 10 healthy volunteers.

Methods

Whole blood was incubated with or without naloxone at a range of concentrations used in septic shock (2 × 10^-4, 2 × 10^-5, 2 × 10^-6, 2 × 10^-7 M). We added dihydrorhodamine 123 to mark H₂O₂ production. We stimulated the cells by either propidium iodide stained S. aureus, E. coli or C. albicans, or by phorbol-myristate-acetate (PMA). We used an index of PH and an index of BO. As H₂O₂ production depends on PH and on BO, wedefined a global index (GI) of its final production taking those two parameters into account.

Results

See Table 1: percentage of change in GI, BO and PH with naloxone compared with no naloxone after stimulation (Wilcoxon signed rank test).

Table 1 abstract P90

Conclusion

Naloxone inhibits significantly in a dose-dependant manner theproduction of H₂O₂ in both neutrophils and monocytes atconcentrations used in septic shock, but its influence on PH and BO is different according to the applied stimulus.