Cardiac interstitial collagen deposition in SHRs and WKY female rats. (a) Quantification of cardiac interstitial collagen from histological analysis. Data indicate differences in % interstitial collagen deposition with respect to strain (SHR versus WKY) and estrogen status (intact versus OVX). Values are reported as means ± SEM; SHR, n = 4 intact and 5 OVX; WKY, n = 5 intact and 4 OVX. Black bars represent gonadal-intact rats; grey bars represent OVX rats. SHR hearts exhibited more collagen deposition than WKY hearts, irrespective of estrogen status (strain effect). There were no estrogen or interaction effects. *p < 0.05 (strain effect). (b) Representative images of LV free wall interstitial collagen deposition were taken at 20× magnification. The picrosirius red-stained slides show modest increases in collagen deposition in hypertensive (SHR) hearts when compared with normotensive (WKY) hearts.
OVX: ovariectomy; SEM: standard error of the mean; SHR: spontaneously hypertensive rat; WKY: Wistar-Kyoto rat.