Apelin decreased cardiac hypertrophy and fibrosis in diabetic mice. (A) Representative H&E histology, periodic acid Schiff (PAS) staining, Masson Trichrome and Pico Sirius Red (PSR) staining in heart sections from C57 and kkAy mice with or without apelin/F13A treatment as quantified in (B, C, D and E) (interventricular septum thickness: diabetes (P = 0.000), treatment (P = 0.000), interaction (P = 0.009); left ventricular wall thickness: diabetes (P = 0.000), treatment (P = 0.000), interaction (P = 0.000); Masson staining: diabetes (P = 0.000), treatment (P = 0.000), interaction (P = 0.036); PSR staining: diabetes (P = 0.000), treatment (P = 0.000), interaction (P = 0.000); n = 6 mice per group, *P < 0.05). Scale bars represent 500 and 50 μm.