Fig. 2

Histological evaluation and angiogenesis in Ptprz1^−/− and Ptprz1^+/+ mouse hearts. A: representative images at ×40 magnification of H&E staining of heart tissue sections from 3 Ptprz1^−/− and 3 Ptprz1^+/+ male mice at the age of 3 mo. B: representative images of WGA-stained heart tissue sections from Ptprz1^−/− and Ptprz1^+/+ male mice. Scale bar corresponds to 50 μm. C and D: the number of cardiomyocytes per mm² and the CSA of 10 cardiomyocytes per slide was measured in at least 4 different slides from each of 3 different mice from each group. Results are expressed as means ± SD of the number of cardiomyocytes per mm² (C) or the calculated cardiomyocyte CSA expressed in μm² (D). E: calculated heart to body ratio expressed as means ± SD (n ≥ 5) at 2 different ages is shown. Statistical analysis was performed by Student’s unpaired t test. Both male (M) and female (F) mice were used, and no difference related to sex has been identified. F: paraffin-embedded hearts from Ptprz1^−/− and Ptprz1^+/+ male mice at the age of 3 wk or 3 mo were stained with rhodamine-conjugated Griffonia simplicifolia for endothelial cells (red). Nuclei were stained with Draq5 (blue). Representative pictures are shown, and scale bars correspond to 50 μm. G: Griffonia simplicifolia lectin-positive endothelial cells per heart area were measured in 2–4 different fields/photo from 3 different animals from each group. Results are expressed as means ± SD of the vascularized cardiac tissue area in arbitrary units (AU). Statistical analysis in all cases was performed by Student’s unpaired t test. CSA, cross-sectional area; H&E, hematoxylin & eosin ; WGA, wheat germ agglutinin.