Effect of LPS (B, C, and D) and ATP (E, F, and G) exposure on the cell viability of SIM-A9 microglia cells (P5 and P6) immediately (B and E), 24 h post-treatment (C and F), and 48 h post-treatment (D and G) using ATP assay. The experimental scheme is shown in A. SIM-A9 cells were cultured in a 96-well-plate at 16,500 cells/well for 48 h. Cells were exposed to 2.5 ng/mL to 50 μg/mL LPS for 2, 4 or 24 h. Cells were treated with 25 nM to 250 μM ATP for 2, 4 or 24 h. The cell viability was evaluated using an ATP assay either immediately, 24 or 48 h post-LPS or ATP treatment. The cell viability of treated cells was calculated relative to control, untreated cells. PEI at 20 μg/mL was used as a positive control. Statistical analysis was performed using GraphPad Prism 8.1.2. Asterisks indicate significant differences (**** p<0.0001, *** p<0.001, ** p<0.005, * p<0.05) compared to the control. The data is representative of two independent experiments and is presented as mean ± standard deviation (SD) of at least n = 4 wells per group.