Introduction. Nitric oxide (NO) is an important diagnostic marker and mediator in the inflammatory process, which plays a key role in the mechanism of programmed cell death, thus, forming the basis of many pathological diseases.
Methods. The study involved 73 newborns with pneumonia (moderate severity in 44 neonates (group 1), severe pneumonia in 29 (group 2)). The intensity of neutrophil apoptosis and necrosis was determined by flow cytometry, whereas nitric oxide metabolites were measured by spectrophotometry.
Results. The level of nitric oxide metabolites (NO2+NO3) in newborns with pneumonia was higher than in healthy children (16.93 (15.82; 17.79) μmol/ml) and correlated with disease severity (in group 1 – 22.65 (21.42; 23.40) μmol/ml in group 2 – 26.82 (25.81; 27.91) μmol/ml). The level of NO3 increased moderately, while NO2 generation was more intense, exceeding control indexes in both groups (рc–1<0.001; рc–2<0.001; р1–2<0.001).
The occurrence of intensive neutrophil apoptosis was revealed in newborns with pneumonia of moderate severity (рc–1<0.001), while necrosis prevailed in severe pneumonia (рc–2<0.001).
Inverse correlation (R=-0.63; р<0.05) was found between the level of nitric oxide metabolites and neutrophil apoptosis; and direct correlation (R=0.68; р<0.05) was revealed between NO metabolites and neutrophil necrosis indices.
Conclusions. Increased generation of nitric oxide metabolites, that directly correlated with disease severity in newborns with pneumonia, was found. NO2 has multidirectional effects on neutrophil apoptosis and necrosis, leading to toxic accumulation of neutrophils in the organism, thus enhancing the inflammatory and intoxication process that impact disease severity.
Key words: nitric oxide, apoptosis, necrosis, neutrophils, pneumonia, newborn