ABSTRACT
Objective To investigate the effects of ketamine on the effector functions (phagocytosis, respiratory burst and release of proteolytic enzymes) of lipopolysaccharide (LPS) stimulated human neutrophils in vitro. Methods Blood samples were collected from healthy volunteers. The study was divided into four groups: LPS group and three ketamine groups (K1, K2 and K3). The final concentration of ketamine in each group was 0, 3, 30 and 300 ?g/ml respectively. Phagocytosis was assessed in whole blood by NBT phagocytosis test (n=8) and respiratory burst by flow cytometry (with dihydrorhodamine 123 as fluorescent marker, n=5). The release of three proteolytic enzymes was measured with isolated polymorphonuclear neutrophils (PMNs) by turbidimetry (lysozyme) and chromatometry (elastase and ? glucurolidase) methods (n=9).Results Ketamine dose dependently inhibited phagocytosis, respiratory burst and proteolytic enzyme releasing of LPS stimulated human neutrophils in vitro. Higher concentrations of ketamine were required to suppress respiratory burst as compared with the concentrations needed to suppress phagocytosis and proteolytic enzyme releasing.Conclusions The inhibitory effects of ketamine on the effector functions of LPS stimulated human neutrophils may contribute to the attenuation of neutrophil mediated inflammatory injuries.
