Delivery of Bay 65-1942 prior to ischemia significantly decreases left ventricular infarct size compared with animals receiving vehicle. Compared with sham animals, animals receiving vehicle have a significant increase in the infarct-to-area at risk (AAR) ratio (70.7±3.4 vs. 5.8±3.4%, P<0.05). This ratio is significantly reduced by treatment with Bay 65-1942 at each time point (prior to ischemia 42.7±4.1%, at reperfusion 42.7±7.5%, 2 h of reperfusion 29.4±5.2%; each group P<0.05 vs. vehicle). Animals pretreated with Bay 65-1942 (n=3) have significantly attenuated CK-MB levels compared with those animals without treatment prior to IR (14,170 ±3,219 units, P<0.05 vs. vehicle).

Inhibitors of MEK (AZD6244) and IKK (BAY 65-1942) are used at their IC ₅₀ concentrations, as determined by a 48 hour MTS assay, which achieve sufficient inhibition of kinase activity. MYL-R cells are treated for 24 hours with AZD6244 (5 μM), BAY 65-1942 (10 μM), or a combination of these inhibitors at the same concentrations. AZD6244 and BAY 65-1942 demonstrate synergistic inhibition of cell viability at the dose combination (5 μM AZD6244+10 μM BAY 65-1942), which correlates with IC ₇₅ (CI = 0.48±0.01). Synergism is also indicated at the IC ₅₀ (CI = 0.56±0.09) and IC ₉₀ (CI = 0.46±0.02) dose combinations reported by the software (CI values are the mean of three independent experiments, ± standard deviation). AZD6244 and BAY 65-1942 treatment induces 2- and 1.3-fold caspase 3/7 activation, respectively, compared to the DMSO-treated cells. Treatment with a combination of AZD6244 plus BAY 65-1942 leads to a 3.2-fold increase in caspase 3/7 activity.