[Basal experiments of active oxygen generation in urinary polymorphonuclear leukocytes]

Abstract

Polymorphonuclear leukocytes (PMNs) play an important role in host defense system. Upon interaction with soluble or particulate matter, PMNs generate active oxygen species (AO), which act on killing of bacteria. In urinary tract infection, urinary PMNs are assumed to have bactericidal activity in urine. Basal experiments were studied on the AO generation of urinary PMNs, monitored by mainly the luminol-dependent chemiluminescence. It was indicated that urinary PMNs, isolated from patients with urinary tract infection, generated AO in physiological medium. This activity of urinary PMNs was found to be significantly inhibited rather than that of PMNs in blood, and this suppression was suggested to be time-dependent. PMNs were affected significantly by osmolarity of reaction medium. These changes were associated with intracellular free calcium. PMNs exposed in hyposmotic medium generated AO, just as they were stimulated. However PMNs exposed in hyperosmotic medium did not generate AO. The stimulation-dependent AO generation of PMNs was increased in hyposmotic solution, while in PMNs incubated at 37 degrees C for 60 min in hyposmotic solution, this generation was decreased than controls. On the other hand, the stimulation-dependent generation was decreased in hyperosmotic solution, while incubated in hyperosmotic solution, this generation was increased. These results suggest that ability of urinary PMNs is regulated by urine osmolarity and retaining time or many other factors, however urinary PMNs are primed and maintain bactericidal activity.