HCQ increases the pro-survival kinase ERK1/2 phosphorylation in simulated I/R injury in neonatal rat cardiomyocytes and is dose-dependent.

Western blot analysis of cell lysates from neonatal rat cardiomyocytes pre-treated overnight with 2000 ng/mL (A) or varying concentrations (250 ng/mL to 2000 ng/mL) of HCQ (B) and the following day exposed to simulated I/R injury (4h hypoxia + 2h reoxygenation) with HCQ present throughout. HCQ increases ERK phosphorylation for both p44 and p42 isoforms. No significant difference is observed in phosphorylation of JNK and Akt after 4h hypoxia + 1h, 2h and 4h reoxygenation (C). Additionally, no difference was observed in phosphorylation of ERK5 in cells pre-treated with HCQ overnight and the following day exposed to simulated I/R injury (4h hypoxia + 4h reoxygenation). Graph shows ±SEM of quantitative analysis from five (A), three (B) and three (C) independent experiments. Statistical analysis determined by 1 way ANOVA using post-hoc Tukey to compare all columns (** p<0.005, ***p<0.0005).