Correlation between generation of nitric oxide and cell viability in human peripheral blood mononuclear cells and leukemic Jurkat T-cell line

Aim: To measure nitric oxide (NO) production in the form of nitrite derivative in relation to cell viability and apoptosis development in human peripheral blood mononuclear cells compared to that processes in human leukemic Jurkat T-cell line. Methods: Apoptosis was induced by dexamethazone (1 mug/ml) or NaNO2 (7 mug/ml) added in the presence or absence of NO-synthase inhibitor N-omega-nitro-L-arginine methyl ester (L-NAME) (27 mug/ml) during cell culturing. Cell viability was determined by trypan blue assay. Apoptosis was measured using DNA "ladder" assay. Results: Dexamethazone and NaNO2 were shown to cause DNA "laddering" in both cell types. L-NAME prevented the appearance of apoptosis in both normal mononuclear cells of peripheral blood and leukemic Jurkat T-cell in the case of dexamethazone action, but it could not prevent it in the case of NaNO2 action. The results of cell viability showed that both the dexamethazone and NaNO2 significantly increased the percentage of dead cells. Their effect was better expressed in Jurkat T-cell line. The levels of nitrite production were higher in the leukemic T-cells comparing to such levels in the normal mononuclear cells. Conclusion: Strong positive correlation was demonstrated between NO production and apoptosis development in both studied cell types, however leukemic Jurkat T-cell line responses were better expressed than such responses in normal mononuclear cells of peripheral blood. Potential significance of that correlation as well as possible mechanisms of appearing differences are discussed.