Fig. 4.

LV collagen loss due to volume overload was increased by ER antagonism. A: representative collagen staining of LV sections by Picrosirius Red (PSR) 5 days and 6 wk after surgery. All volume-overloaded groups exhibited a loss of interstitial collagen. ER antagonism with ICI exacerbated the loss of interstitial collagen seen in the volume-overloaded groups. Image brightness was increased for presentation (scale bar = 300 μm). B: collagen volume fraction (CVF) calculated from PSR-stained ventricular sections. Interstitial CVF was significantly reduced at 5 days and 6 wk postsurgery in both volume-overloaded groups (ACF and ACF + ICI) relative to Sham. Treatment with an ER antagonist (ICI) led to further loss of collagen (n = 4–5 in all groups; *P < 0.05 vs. Sham; †vs. ACF).