Adult proNgf-HA/⁺ mice exhibit dilated cardiomyopathy, fibrosis, and contractile dysfunction. (A–C) H&E-stained sections of hearts from 8-mo-old Ngf^+/+, proNgf-HA/⁺, and p75^−/−;proNgf-HA/⁺ mice. (D–F) Higher magnification images. (G–I) Masson’s trichrome analysis of hearts from 8-mo-old Ngf^+/+, proNgf-HA/⁺, and p75^−/−;proNgf-HA/⁺ mice. Red, myocardium. Black, nuclei. Blue, collagen matrix. (J) Quantification of cardiac fibrosis in 6–8-mo-old proNgf-HA/⁺ mice and Ngf^+/+ littermate mice. Three to four fields of view from the subendocardium were analyzed for each animal and was averaged. Mean ± SEM, n = 4/genotype. (K) Fractional shortening in proNgf-HA/⁺ mice (solid red squares) compared with Ngf^+/+ (blue diamonds), p75^−/−:proNgf-HA/⁺ (open red squares), and sort^−/−:proNgf-HA/⁺ mice (filled green triangles). ***, P < 0.005 proNgf-HA/⁺ compared with Ngf^+/+; #, P < 0.05 sort^−/−:proNgf-HA/⁺ compared with Ngf^+/+, Student’s t test. Solid blue and red, and dashed red and green lines, linear regression curve for each genotype. (L) Kaplan-Meier graph of survival of Ngf^+/+ (solid blue line), proNgf-HA/⁺ (solid red line), p75^−/−;proNgf-HA/⁺ (red dotted line), and sort^−/−;proNgf-HA/⁺ (green dotted line) mice. Bars: (A–C) 2 mm; (D–I) 100 µm. (A–I, K, and L) Ngf^+/+, n = 18; proNgf-HA/⁺, n = 31; p75^−/−;proNgf-HA/⁺, n = 14; sort^−/−;proNgf-HA/⁺, n = 15.