A, Representative trichrome-stained photomicrographs obtained from cardiac tissue derived from the different experimental groups. B, Amount of fibrosis expressed as the mean±SEM measured using computer-assisted morphometry, as we have described previously.15 C, Representative (top) and quantitative analysis of collagen 1 (mean±SEM) Western blots performed on cardiac tissues from the different groups. Actin was used to control loading. Control refers to animals subjected to sham surgery (n=8); S refers to spironolactone infusion using minipumps (n=8); PNx refers to partial nephrectomy (n=10); and MBG refers to MBG infusions using minipumps (n=8). PNx S (n=6) and MBG+S (n=6) refer to combining those 2 maneuvers. †P<0.01 vs control, §P<0.01 vs PNx, ¶P<0.01 vs MBG.