Figure 1. Young and aged cardiac extracellular matrix can be decellularized while retaining matrix protein content. (A) Picrosirius histological staining of collagen deposition in cardiac tissue samples isolated from mice of 1 month, 12 months, and 23 months of age. (B) Quantification of the percent area of positive picrosirius red expression per field of view for tissue samples from 1 month, 12 month, and 23 month old mice. (C) Alcian blue staining of sulfated proteoglycans in cardiac tissue samples isolated from mice of 1 month, 12 months, and 23 months of age. (D) Hydroxyproline mass percentage and (E) glycosaminoglycan mass percentage for both young and aged native as well as young and aged decellularized cardiac samples. (F) 4’,6-diamidino-2-phentylindole (DAPI) nuclear staining of native and decellularized tissue samples (G) Quantification of dsDNA content isolated from young and aged either native or decellularized cardiac tissue samples. Values shown represent mean with 25%/75%. Error bares represent standard deviation. N=4-5; * p<0.05; Scale bars (A, C) = 1mm; Scale bar (F) = 100um. Independent samples t-test used to assess significant trends in (D, E). One-way ANOVA with post-hoc Tukey’s test used to assess significant trends in (G).