6533b855fe1ef96bd12b1252

RESEARCH PRODUCT

Inhibitory effects of N-acetylcysteine on the functional responses of human eosinophils in vitro

subject

description

Background Oxidative stress appears to be relevant in the pathogenesis of inflammation in allergic diseases like bronchial asthma. Eosinophils are oxidant-sensitive cells considered as key effectors in allergic inflammation. Objective The aim of this work was to study the effects of the clinically used antioxidant N-acetyl-L-cysteine (NAC) on the functional responses of human-isolated eosinophils. Methods Human eosinophils were purified from the blood of healthy donors by a magnetic bead separation system. The effects of NAC were investigated on the generation of reactive oxygen species (chemiluminescence and flow cytometry), Ca2+ signal (fluorimetry), intracellular glutathione (GSH; flow cytometry), p47(phox)-p67(phox) translocation (Western blot) and eosinophil cationic protein (ECP) release (radioimmunoassay). Results NAC (0.1-1 mM) inhibited the extracellular generation of oxygen species induced by N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) and eotaxin (in the presence of IL-5) with -logIC(50) values of 3.61 +/- 0.03 and 3.36 +/- 0.09, respectively. Also, the intracellular generation of hydrogen peroxide was virtually abolished by NAC (0.5-1 mM). NAC (1 mM) did not alter the fMLP-induced Ca2+ signal but augmented the eosinophil content of reduced GSH and inhibited p47(phox)-p67(phox) translocation. NAC inhibited the release of ECP (similar to 90% inhibition at 1 mM) from fMLP-activated eosinophils. Conclusion Inhibition by NAC of human eosinophil functions in vitro is potentially useful in the treatment of allergic inflammation.