Implanted MDSC stimulated angiogenesis and reduced myofibroblasts, without affecting PDE 5 expression, while concurrent sildenafil protected the endothelium but increased myofibroblasts and upregulated PDE5. (n = 7/group). Protein extracts were obtained from region #3 adjacent to the infarction area and subjected to western blot analysis. A: representative immunoblots (n = 8), indicating band sizes. B: PDE 5 assayed in MDSC cultures in duplicate. C: Densitometric values corrected by GAPDH. Statistical differences are stated for untreated versus basal, and MDSC, and MDSC + sildenafil versus untreated; *p < 0.05; **p < 0.01;***p < 0.005.