Figure 4: Effects of Ang II on Interstitial Fibrosis in the SAN of Wild-Type and NPR-C

(A) Sections through the SAN in wild-type and NPR-C−/− mice treated with saline or Ang II. For each treatment group, the top image illustrates the HCN4-positive zone (green) used to identify the SAN region, and the bottom image illustrates the picrosirius red staining from an adjacent section used to identify fibrosis (red). Bars = 50 μM. (B) Summary of SAN fibrosis measured in the HCN4-positive zone for wild-type and NPR-C−/− mice treated with saline or Ang II. *p < 0.001 versus saline; +p = 0.014 versus wild type by 2-way analysis of variance with Tukey post hoc test; n = 5 hearts for each group.