Figure 7. 17β-Estradiol ameliorates cardiac parasympathetic dysfunction following MI in male mice.

(A) Plasma E2 levels from E2 + MI animals were confirmed to be elevated versus MI-only animals (P < 0.01, n = 6 per group). (B and C) BRS improved (P < 0.05), and there was a trend for improvement in the ratio of ΔRR/ΔBP (P = 0.06) in E2 implanted infarcted (E2 + MI) versus MI-only male mice (n = 6 per group), while no significant differences were noted between sham (n = 7) and E2 + MI males. (D) E2 + MI males also demonstrated improved HR responses to optogenetic stimulation compared with MI-only animals (P < 0.01). No significant differences between E2 + MI versus sham males were noted. (E) Similar to HR, blood pressure responses in E2 + MI animals were restored with estradiol (P < 0.001 for E2 + MI versus MI-only males, n = 6 per group) and were similar to sham (n = 7) animals. (F) Vagal ganglia were isolated (n = 12 ganglia/sample per group, 3 independent samples), and 4-HNE levels were quantified. 4-HNE levels were significantly lower in E2 + MI versus infarcted males (P < 0.05) and were not statistically different from sham male mice. Data are shown as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001 for comparisons of E2 + MI versus MI. Unpaired Student’s t test was used for comparison of E2 levels. One-way ANOVA with the FDR corrected for by the Benjamini-Hochberg procedure was used for the comparison of MI versus E2 + MI versus sham groups. Data are shown as mean ± SEM.