PMC

Flow diagram summarizing the manner in which estrogen replacement differentially influences Stat3 phosphorylation and hypertrophy in the mouse MI and TAC models.

A. ANP Gene Expression. Measured semi-quantitatively using multiplex rtPCR, simultaneously measuring GAPDH and ANP. The figure represents an example of an ethidium bromide-stained agarose gel from which ANP gene expression (above) was quantified by densitometry, correcting for GAPDH levels (below). B. β-MHC Gene Expression: Measured by multiplex rtPCR as with ANP. * p<0.01 vs. the respective sham group. † p<0.05 vs. placebo-MI. ‡p<0.05 vs. placebo-TAC. ** p<0.01 vs. placebo-TAC. § p=0.09 vs. E2-Sham

All data are means±sem; bar graphs represent echocardiographically derived LV chamber size and function; LV mass was measured immediately post-mortem. LV end diastolic diameter (LVEDD), end systolic diameter (ESD), and LV mass are indexed to femoral length (FL). MI=myocardial infarction; TAC=transverse aortic constriction; E2=17β-estradiol; FS=fractional shortening. * p<0.01 vs. the respective sham group; † p=0.09 vs. placebo-shams; ‡ p<0.05 vs. placebo-TAC; ** p<0.05 vs. the respective sham group.

Activation of these signaling kinases was assessed by western blotting for the activated, phospho-form, correcting for total kinase levels. Data represent the fold increase vs. the respective sham group (not included). Placebo groups (N=4 each for Sham, MI and TAC at each time point) are represented in open squares with black lines that are either solid (TAC) or dashed (MI); Estrogen groups (N=4 for Sham, MI and TAC at each time point) are depicted as black circles with grey lines that are either solid (TAC) or dashed (MI). The western blots shown are representative of the 48-hour time point. Data are means±sem. A. ERK1/2 Activation. *p<0.01 TAC (E2 and placebo) vs. sham and MI groups within a given time point. B. p38 MAPK Activation. * p<0.05 TAC (E2 and placebo) vs. sham and MI groups within a given time point. † p<0.05 MI (E2 and placebo) vs. shams. No significant differences were observed between E2 and placebo groups in the activation of these signaling kinases following MI or TAC. C. Stat3 Activation. *p<0.05, MI or TAC (placebo and E2) vs. shams; † p<0.05 E2-MI vs. E2-shams; ‡p<0.05 E2-MI vs. E2-shams and placebo-MI. **p<0.05 placebo-TAC vs. placebo-shams. †† p<0.05 E2-TAC vs. placebo-TAC. 2 way-ANOVA revealed a signficant treatment by procedure interaction supporting that the effect of E2 treatment on Stat3 activation differed between the MI and TAC models (p<0.05 at 24 hours and p<0.01 at 48 hours).