Fig. 2

Kinetics of NO production in the culture supernatants of PK-15 cells. When 80% confluent monolayers formed, 125 μM GSNO or 125 μM GSNO plus Hb (5, 10, 20 μM) were added into 96-well cell culture plates, with four wells for each concentration, and untreated cells served as the control. The supernatant from each sample was collected at different time points, and the NO levels were determined by Griess reaction with a microplate reader at 540 nm according to a standard curve made from sodium nitrite. Data were presented as means ± SD from three independent experiments. *P < 0.05, **P < 0.01 vs 125 μM GSNO-treated group