Neutralising effect of an extract from neutrophils (NE) on stimulating influence of LPS E.coli and Intralipid on metabolic activity of cells in the NBT reduction test
Ewa Pawłowska, Gabriel Turowski
Med Sci Monit 1999; 5(2): BR186-192
The effect of neutrophil extract (NE) was investigated on the model of cytochemical reaction of peripheral blood neutrophils in NBT reduction tests. The experiments were performed in standard conditions of stimulated reduction test NBTst, using the following factors for neutrophil stimulation: NE, LPS E. coli, IntralipidR (ILP) as well as NE+LPS, NE+ILP and NE+LPS+ILP. The index of differences of NBT-positive cells after stimulation and without stimulation was also used for the interpretation of results (NBTst - NBTnst). Stimulating effect of LPS, ILP and LPS+ILP on the results of NBTst test was confirmed. Differences in the results in relation to NBTnst results were highly statistically significant. Prepared neutrophil extract (NE) proved active and it inhibited the effect of both endotoxin E. coli and IntralipidR in performed experiments in the doses of 4.0 µg LPS and 2.0 mg ILP. Observed differences were highly statistically significant. Neutrophil extract alone (NE) had two effects. It stimulated suspension of neutrophils isolated from 5 different subjects for increased NBT salt reduction. The difference in relation to control NBTnst test were highly statistically significant (t = 5.82, p<0.0043). In the case of neutrophil suspensions from 5 other persons, the effect of NE was different and the differences were not significant (t = Ð2.34). The distribution of the results of NBT reduction tests as a consequence of the use of NE+LPS, NE+ILP and NE+LPS+ILP on neutrophil suspension applied in the tests indicated their different abilities for the response to stimulation. On the basis of the results obtained in our experiments, it may be suggested that neutralising effect of peripheral blood neutrophils in relation to endotoxins of Gram-negative bacilli is the main function of these cells in septic states. Intensified leukocytosis of peripheral blood also seems to confirm this claim. Pathomechanism of these phenomena is still a subject of discussion.
Keywords: neutrophils activity, neutrophil extract, LPS E. coli, Intralipid, NBT reduction test