Figure 3. AT_1A deficiency protects heart from hypertrophy and fibrosis.

Paraffin-embedded hearts (Agtr1a^–/– mice, n = 7, 26 to 30 months old; wild-type mice, n = 4, 26 to 29 months old) were sectioned at 5 μm for hematoxylin-eosin for morphometric studies and at 10 μm for collagen content stained with picrosirius solution. (A) Neither the ratio of heart weight/body weight, (B) nor the estimated number of left ventricular cardiomyocytes were effected by the absence of AT_1A. (C) The cross-sectional area of cardiomyocytes, an index of hypertrophy, and (D) interstitial collagen, a marker of cardiac fibrosis, were significantly lower in Agtr1a^–/– mice. Data are mean ± SD. *P < 0.01 versus wild-type mice by Student’s t test for impaired data.