Figure 3. Correlation analysis of Omi/HtrA2 mRNA expression and cardiac reserve function with aging. The mRNA levels of Omi/HtrA2 were assessed by quantitative RT-PCR (A). Protein expression was evaluated by western blotting (B). Data are represented as mean +/- SEM, n = 6 per group. *P<0.05, **P<0.01 vs. 4m. m=month. A strong negative correlation between Omi/HtrA2 mRNA expression and ejection fraction (EF, %) was observed with aging (C). A significant linear negative correlation between Omi/HtrA2 mRNA expression and fractional shortening (FS, %) with aging (D). No significant linear correlation between Omi/HtrA2mRNA expression and E/A ratio (E). No significant linear correlation between Omi/HtrA2 mRNA levels and left ventricular end-systolic diameter (LVID, mm) was observed (F). The correlation analysis between Omi/HtrA2 mRNA levels and left ventricular posterior wall end-systolic thickness (LVPW, mm) (G). Correlation analysis between Omi/HtrA2 mRNA levels and left ventricular mass (LV mass, mg) (H). A significant linear negative correlation between Omi/HtrA2 mRNA expression and heart/body weight with aging (I).