Quantification of Western blot analyses for collagen types-I, type-III, and type-IV, normalized to α-tubulin.

<p><b>A.</b> Collagen-type I: expression levels of immature (pro) and mature forms of collagen type-I increase significantly with age in WT hearts and are similar between 2 yr old WT and 2 mo old D3KO. <b>B.</b> Collagen type-III: expression levels of collagen type III were similar in young and old WT hearts and were not significantly different in D3KO. <b>C.</b> Collagen type-IV: as with collagen type-III, expression levels of collagen type-IV were similar in the hearts of young and old WT and D3KO.