ECM microarchitecture and composition in young and aged ECM-based scaffolds. (a) Masson’s Trichrome staining showed the persistence of collagen fibers (blue) and their comparable distribution between native (Native) and decellularized ovaries (Scaffold) belonging to the same age. (b,c) Stereological (b) and ELISA quantifications (c) demonstrated no significant differences between native ovaries (Native) and the decellularized ECM-based scaffolds (Scaffold) in collagen content. Data are expressed as the mean. Error bars represent the standard error of the mean (SEM), ** p < 0.01; (d) Gomori’s aldehyde-fuchsin staining indicated that ECM-based scaffolds (Scaffold) retained the elastic fibers scattered throughout the decellularized ovary, similar to what was visible in untreated young and aged ovaries (Native). (e,f) Stereological (e) and ELISA quantifications (f) confirmed no significant differences between native ovaries (Native) and the decellularized ECM-based scaffolds (Scaffold) in elastin content. Data are expressed as the mean. Error bars represent the standard error of the mean (SEM), ** p < 0.01; (g) Alcian blue staining revealed GAG retention in young and aged decellularized scaffolds (Scaffold). Scale bars = 100 μm; (h,i) Stereological (h) and ELISA quantifications (i) demonstrated no significant differences between native ovaries (Native) and the decellularized ECM-based scaffolds (Scaffold) in GAG content. Data are expressed as the mean. Error bars represent the standard error of the mean (SEM), * p < 0.05.