Fig. 4

Changes in the medium induced by 2 h AC electrical stimulation (ES). A Temperature measurements during ES. Stimulation was performed inside the incubator with a target temperature of 37 °C (mean, n = 3 independent experiments). B Significantly higher H2O2 concentration in ES medium without pyruvate over the course of 8 h. Note the rapid decline of H2O2 up to 24 h (mean ± s.e.m., n = 2–3 independent experiments). C H2O2 concentration after 2 h ES in culture medium without and with 1 mM pyruvate added as ROS scavenger (mean ± s.e.m., n = 3 independent experiments). B and C: Two-way RM ANOVA with Bonferroni posttests, compared to control