Figure 4: Pi infusion attenuates H2O2-induced ROS production in astrocytes. Astrocytes were preloaded with the redox-sensitive DCF-DA for 30 min and washed with PBS. Preloaded astrocytes were then pre-incubated with various concentrations of Pi infusion for 2 h. H2O2 (175 μM) was added to the culture and the fluorescence intensity representing ROS production was measured. (a) The fluorescence levels of cells that had been preincubated with 100 μg/mL Pi extract were measured at the indicated time points. Compared to cells treated with H2O2 only. (b) The fluorescence levels of cells that had been pre-incubated with various concentrations of Pi extract were measured after 3 h. Each point represents the mean ± SEM of two experiments (). .