Histological analyses of tissue damage indicators in representative serial sections of hearts from vehicle and NBD peptide treated dko mice show similar pathology in both treatment groups. A. Hematoxylin and eosin (H&E) staining shows the presence of fibrotic scars in dko hearts from vehicle and NBD-treated groups. B. Immunostaining for collagen I shows localization of collagen in fibrotic regions. C. ER-TR7 immunostaining demonstrates fibroblasts are a major cellular infiltrate in regions of fibrosis. D. CD-45 immunostaining shows that immune cells are not detected in fibrotic scars at the time-point of analysis. Scale bar equals 50 μm.