Sex Difference in Cardioprotection against Acute Myocardial Infarction in MAO-B Knockout Mice In Vivo

Figures

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  Figure 1. Higher mortality rate in male wild-type (WT) and cardiomyocyte-specific MAO-B knockout (KO) mice compared to female mice. WT and KO hearts were exposed to 45 min ischemia and 120 min reperfusion. Summary of the number of operated mice before and after surgery. Excluded mice had blood in the urine or surgery complications. There is no significant difference among groups when analyzed groups separately by Chi-square test or between WT and KO animals when analyzed by Fisher’s exact test. However, there is a slightly decreasing tendency but not significant in all-cause mortality in female individuals as compared to males when analyzed by Fisher’s exact test (* p = 0.103).

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  Figure 2. Male MAO-B KO mice benefit from MAO-B deletion regarding reduced size of infarcted area. (A) shows quantification of area at risk and (B) infarct size quantification. (WT male n = 14; WT female n = 9; KO male n = 11; KO female n = 11). Data are represented as box plots expressing median, 25% and 75% quartiles, upper and lower whisker and outliers. * p < 0.05 WT male vs. WT female, KO male, KO female, Student’s t-test.

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  Figure 3. In male wild-type (WT) mice, heart rate did not increase following ischemia/reperfusion. WT and cardiomyocyte-specific MAO-B knockout (KO) hearts were exposed to 45 min ischemia and 120 min reperfusion. Heart rate was measured baseline and after reperfusion. (WT male n = 14; WT female n = 9; KO male n = 11; KO female n = 11). Data are represented as box plots expressing median, 25% and 75 % quartiles, upper and lower whisker and outliers (○,). * p < 0.05, *** p < 0.001 baseline vs. after reperfusion, Student’s t-test. Two-way ANOVA: p < 0.001, baseline vs. after reperfusion p < 0.001, genotype * sex p = 0.02.

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  Figure 4. Violin plot representing the severity and duration of reperfusion arrhythmias. (WT male, male wild-type mice; KO male, male MAO-B knockout mice; WT female, female wild-type mice; KO female, female MAO-B knockout mice). * p = 0.014 when WT and KO males are compared to WT and KO females as analyzed by Mann–Whitney test.

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  Figure 5. Heart weight (HW) and body weight (BW) as well as HW/BW ratios of mice. Female mice had reduced heart weight (A), *** p < 0.001 male vs. female and ### p < 0.001 WT male vs. KO female, Student’s t-test; two-way ANOVA: sex p < 0.001. Female mice had reduced body weight (B) compared to male mice, *** p < 0.001 male vs. female, ### p < 0.001 WT male vs. KO female, Student’s t-test; two-way ANOVA: sex p < 0.001. HW/BW ratios (C) were similar in WT males and females as well as in male cardiomyocyte-specific knockout (KO) mice, while in female KO mice HW/BW ratio was reduced, * p < 0.05 KO male vs. KO female and ## p < 0.01 WT male vs. KO female, Student’s t-test. Two-way ANOVA: sex * genotype p = 0.088. (WT male n = 14; WT female n = 9; KO male n = 11; KO female n = 11). Data are represented as box plots expressing median, 25% and 75 % quartiles, upper and lower whisker and outliers (○,).