CHF upregulates JAK-STAT components in dogs. (A, B) mRNA expression of JAK1 and JAK2 in LA and LV fibroblasts as a function of VTP time. Mean ± S.E.M., n = 5–12/group, *P < 0.05, **P < 0.01, vs. CTL. (C) Representative immunoblots for phosphorylated STAT3 (p-STAT3) and t-STAT3 from atrial and ventricular tissue. (D–F) Band-intensities for p-STAT3, t-STAT3 (normalized to GAPDH), and phosphorylated-STAT3/t-STAT3 ratio. Mean ± S.E.M., n = 5/group, *P < 0.05, **P < 0.01, ***P < 0.001. One-way ANOVA with Dunnett’s tests (A and B) or Bonferroni-corrected t-tests (D–F) were used for statistical analysis. FB, fibroblast; LA, left atrial; LV, left ventricular; CTL, non-paced controls; CTL-A, control atrium; CTL-V, control ventricle; CHF-A, congestive heart failure atrium; CHF-V, congestive heart failure ventricle.