Figure 3: Time course analysis of intracellular ROS levels changes caused by catalase and Mn complexes 1 and 2 treatment.

The neurons were incubated with two concentrations of catalase (CAT), complex 1 and complex 2 for 1 h, 12 h and 24 h, respectively. Collected cells were incubated with DCFH for 20 min at 37 °C. The fluorescence of DCF was measured by a flow cytometer. ROS levels are expressed as a histogram of the DCF fluorescence generated by 20,000 cells. Treatment with only normal culture medium without drug stimulation served as control. The fluorescence intensity of each sample was expressed as the percent (%) of control values, which were shown in dotted line at the value of 100%. The columns representing lower doses (0.01 mg/ml of CAT, 1 μM of 1 and 0.1 μM of 2) treatment were filled with the sparse slashes pattern, while that representing higher doses (0. 1 mg/ml of CAT, 10 μM of 1 and 1 μM of 2) treatment were filled with the dense pattern. The data are presented as mean ± SD of three independent experiments (Student’s T. Test, *P < 0.05, **P < 0.01 vs. control).