Figure 1
RCC4-EV cells are more resistant to lidocaine-induced cell injury than RCC4-VHL cells. RCC4-VHL and RCC4-EV cells were exposed to the indicated concentrations (1, 4, or 10 mM) of lidocaine for varying lengths of time (0, 12, 24, and 48 h). (a,b and c) Graphic depictions of caspase-3/7 (n = 5) (a and b) and caspase-9 (n = 5) (c) activity in each treatment group at different time points (d) Cells were harvested and cell death percentages were measured with flow cytometry. The ratio of propidium iodide (PI)-positive and/or annexin V-positive cells [(Q1 + Q2 + Q4)/(Q1 + Q2 + Q3 + Q4)] was used to calculate the percentage of dead cells (Supplemental Fig. S1) (n = 3). (e) Graphic depiction of cell death percentages in treated and untreated cell populations. Cell death was evaluated by measuring the levels of lactate dehydrogenase (LDH) within culture supernatants (n = 4). Control is treatment with lysis buffer. (f) Graphic depiction of the average mitochondrial membrane potential (ΔΨm) of treated and untreated cells (n = 3) at each time point. Values indicate the ratio [Q2/(Q2 + Q4)] of green JC-1 monomers (527 nm emission) to red aggregates (590 nm emission). Data presented in (a–f) are expressed as mean ± standard deviation (SD). Differences between results were evaluated by two-way ANOVA followed by Dunnett’s test for multiple comparisons (a, c–f) or one-way ANOVA followed by Dunnett’s test for multiple comparisons (b). *p < 0.05 compared to the control cell population at incubation time 0 h (no treatment). # p < 0.05 compared to the control cell population at the same lidocaine concentration (group).
