Age-Dependent Changes in Calcium Regulation after Myocardial Ischemia–Reperfusion Injury

Figures

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  Figure 1. Schematic representation of the experimental protocol. A model of myocardial ischemia and reperfusion using rats of three age groups and subdivided into control group (CON), ischemic group (ISCH), and ischemia-reperfusion group (IR).

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  Figure 2. Effect of IR on contractile function parameters during aging. Individual parameters are presented as (A) coronary flow, (B) heart rate, (C) LV +dP/dt (maximum rate of pressure development), and (D) LV −dP/dt (maximum rate of relaxation). Values are expressed as mean ± SD of 5 hearts per each experimental group, * p < 0.05, ** p < 0.01, *** p < 0.001, significantly different when compared to the preischemic value, or ++ p < 0.01, +++ p < 0.001, significantly different when compared between age groups.

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  Figure 3. Recovery of LV devP after myocardial IR during aging. Values are expressed as mean ± SD of 5 hearts per each experimental group. p > 0.05 represents tendency but no significant changes between age groups. LV devP is Left Ventricular developed Pressure.

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  Figure 4. Calcium dependence of Ca2+-ATPase activity during aging in CON, ISCH, and IR groups. The nonlinear least-squares method with Hill fitting was used for the graphical interpretation of Ca2+ dependence. Values are expressed as mean ± SD of 5 hearts per each experimental group. * p < 0.05, ** p < 0.01, significantly different when compared to the CON, or + p < 0.05, ++ p < 0.01, significantly different when compared between age groups.

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  Figure 5. The relative protein levels of (A) SERCA2a and (B) PLN after IR in aged hearts. The total PLN amount is presented as the sum of PLN monomers and oligomers. Values are expressed as mean ± SD of 3 hearts per each experimental group. * p < 0.05, *** p < 0.001, significantly different when compared to the CON, or + p < 0.05, ++ p < 0.01, +++ p < 0.001, significantly different when compared between age groups. SERCA2a (SR/ER Ca2+-ATPase), PLN (phospholamban).

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  Figure 6. Representative dot blots with the relative protein levels of IP3R (A) and RyR (B) after IR in aged hearts. Values are expressed as mean ± SD of 3 hearts per each experimental group. * p < 0.05, significantly different when compared to the CON, or + p < 0.05, ++ p < 0.01, significantly different when compared between age groups. IP3R (inositol 1,4,5-trisphosphate receptor), RyR (ryanodine receptor).

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  Figure 7. Representative Western blots with the relative protein levels of NCX1 (A), MCU (B), VDAC1 (C), and GRP75 (D) after IR in aged hearts. Values are expressed as mean ± SD of 3 hearts per each experimental group. * p < 0.05, significantly different when compared to the CON, or + p < 0.05, ++ p < 0.01, significantly different when compared between age groups. NCX1 (Na+/Ca2+ exchanger), MCU (mitochondrial Ca2+ uniporter), VDAC1 (voltage-dependent anion channel 1), GRP75 (glucose-regulated protein 75).