Fig. 5.

Sex- and age-specific differences in the recovery of contractile function during reperfusion. All data were normalized to the baseline values. a LVDP recovered significantly better in the hearts from old males compared to young males in reperfusion. There was also a significant effect of sex in the young adult group, where young females recovered significantly better than young males. The recovery of b RPP, c +dP/dt, and d −dP/dt in the old male hearts was also significantly better than in the young male hearts, although the effect of sex was only significant in late reperfusion for +dP/dt. By contrast, e LVDP, f RPP, g +dP/dt, and h −dP/dt recovered to the same extent in the female hearts, regardless of age. Values are expressed as the mean ± SEM. Results were analyzed with a three-way mixed ANOVA with two between factors (age, sex) and one within factor (time). The asterisk denotes significantly different from young male (p < 0.05); the number sign denotes significantly different from young female (p < 0.05). Detailed statistical analysis is presented in Additional file 2: Table S2. Young male, n = 5; old male, n = 6; young female, n = 6; old female, n = 5