Figure 6: Pi infusion is similarly effective in attenuating ROS production when applied before or after H2O2. Pi infusion (12.5 μg/mL) was added to astrocytes before (−2 h, −1 h) or after (1 h, 2 h) the addition of H2O2. ROS levels in DCF-DA preloaded astrocytes were measured 1, 4, and 6 h after the application of H2O2. The results are mean ± SEM of two experiments ( ). .