Rats were dosed by gavage with 200 mg/ml HCQ for three days prior to surgery (1h occlusion of LAD artery + 24h reperfusion) and when sacrificed hearts were stained with Evans blue and TTC to assess infarct size (IS) (B) and area at risk (AAR) (C). Graphs A, B and C show mean ±SEM of quantitative analysis from ten control, six U0126 treated, eleven HCQ treated and five HCQ + U0126 treated rats. Blood levels of HCQ were detected using HPLC (D). Rats were treated with 1 mg U0126, 30 minutes prior to surgery to inhibit ERK1/2 phosphorylation. Graphs e and f show mean ±SEM of quantitative analysis from four control, four HCQ treated and five HCQ + U0126 treated rats. Statistical analysis determined by unpaired t-test (*** p = 0.0002, ** p = 0.0077)(A), (** p = 0.0022, ** p = 0.0097)(C) and one way ANOVA with Tukey post hoc analysis (* p<0.5, *** p<0.0005)(E+F).