Figure 1.
Effects of dexamethasone on AT1R and AT2R mRNA and protein.
Hearts were isolated from animals treated with vehicle control, dexamethasone (DEX), DEX + RU486 (RU). AT1R and AT2R protein (A) and mRNA (B) abundance was determined by Western blots and real time RT-PCR, respectively. Data are means ± SEM. Data were analyzed by one-way ANOVA. * P<0.05, DEX vs. control or DEX+RU486, n = 4.
Figure 2.
Effects of dexamethasone on cardiac ischemia and reperfusion injury.
Hearts were isolated from animals treated with vehicle control, dexamethasone (DEX), DEX + RU486 (RU), and were subjected to 20 minutes of ischemia and 30 minutes of reperfusion injury in a Langendorff preparation. Losartan (L, 1 µM) and PD123319 (PD, 0.3 µM) were added 5 minutes before ischemia and continuously present in the perfusion buffer during ischemia/reperfusion period. Post-ischemic recovery of left ventricular function and infarct size were determined. LDH release over 30 minutes of reperfusion was measured as area under curve (AUC). Data are means ± SEM. Data were analyzed by two-way ANOVA. * P<0.05, DEX vs. control or DEX+RU486, n = 6.
Figure 3.
Effects of individual application of losartan and PD123319 on dexamethasone-induced cardiac protective effect.
Hearts were isolated from animals treated with vehicle control or dexamethasone (DEX) and were subjected to 20 minutes of ischemia and 30 minutes of reperfusion injury in a Langendorff preparation. Losartan (L, 1 µM) or PD123319 (PD, 0.3 µM) were added 5 minutes before ischemia and continuously present in the perfusion buffer during ischemia/reperfusion period. Post-ischemic recovery of left ventricular function and infarct size were determined. Data are means ± SEM. Data were analyzed by two-way ANOVA. * P<0.05, DEX vs. control or DEX+L, n = 4-9.
Table 1.
Pre-ischemic left ventricular functional parameters.
Figure 4.
Effects of dexamethasone on GR protein abundance.
Hearts were isolated from animals treated with vehicle control, dexamethasone (DEX), DEX + RU486 (RU). Total and nuclear GR protein abundance was determined by Western blots. Data are means ± SEM. Data were analyzed by one-way ANOVA. * P<0.05, DEX vs. control or DEX+RU486, n = 4.
Figure 5.
Effects of dexamethasone on GR binding affinity to GREs at the AT1aR and AT2R promoters.
Hearts were isolated from animals treated with vehicle control, dexamethasone (DEX), DEX + RU486 (RU). Competition EMSA was performed with pooled nuclear extracts (n = 5) with the increasing ratio of unlabeled/labeled oligonucleotides encompassing the GRE2 at the AT1aR promoter (A) or the GRE4 at the AT2R promoter (B). Data are means ± SEM. The slopes were analyzed by one-way ANOVA. * P<0.05, DEX vs. control or DEX+RU486.
Figure 6.
Effects of dexamethasone on GR binding to GREs at the AT1aR and AT2R promoters.
Hearts were isolated from animals treated with vehicle control, dexamethasone (DEX), DEX + RU486. Binding of the GR to GREs at the AT1aR (A) and AT2R (B) promoters was determined by ChIP assays using a GR antibody. Data are means ± SEM. Data were analyzed by one-way ANOVA. * P<0.05, DEX vs. control or DEX+RU486, n = 5.
Figure 7.
Effects of dexamethasone on PKCε and PKCδ expression.
Hearts were isolated from animals treated with vehicle control, dexamethasone (DEX), DEX + RU486 (RU). PKCε, PKCδ, p-PKCε, and p-PKCδ protein abundance (A) and PKCε and PKCδ mRNA abundance (B) were determined by Western blots and real time RT-PCR, respectively. Data are means ± SEM. Data were analyzed by one-way ANOVA. * P<0.05, DEX vs. control or DEX+RU486, n = 4.