Eriodictyol Attenuates Myocardial Ischemia-Reperfusion Injury through the Activation of JAK2

Figures

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  FIGURE 1. Eriodictyol (EDT) treatment rescues myocardial injury in an ex vivo model of global myocardial I/R. The effect of EDT on LVDP (A), +dP/dtmax (B), –dP/dtmax (C), and CF (D) in rat hearts were measured using PowerLab data acquisition device. The values of these parameters were normalized to the values of the recorded data before 15 min of zero-flow global ischemia. The levels of LDH (E) and CK (F) in K–H buffer were determined by commercial kits. (G) The infarct size was examined by TTC staining after EDT treatment. Scale bar: 1 mm. n = 8 for each group. All data are the mean ± SD. ∗P < 0.05 compared with control group, #P < 0.05 compared with I/R group.

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  FIGURE 2. Eriodictyol treatment suppresses the elevated levels of IL-6, CRP, IL-8, and TNF-α induced by I/R. The effect of EDT on IL-6 (A), CRP (B), IL-8 (C), and TNF-α (D) levels in cardiac tissues were measured by ELISA kits. n = 8 for each group. All data are the mean ± SD. ∗P < 0.05 compared with control group, #P < 0.05 compared with I/R group.

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  FIGURE 3. Eriodictyol treatment inhibits the cardiomyocyte apoptosis induced by I/R injury. (A) The cardiomyocyte apoptosis was examined by TUNEL assay. Brown staining of the nucleus indicates cell apoptosis. Scale bar: 20 μm. (B) The protein levels of Bax, Bcl-2 and cleaved Caspase-3 in cardiac tissues were measured by western blot. (C) Statistical analysis of Bax, Bcl-2 and cleaved Caspase-3 protein levels in cardiac tissues. n = 4 per group. The protein ratios were normalized to the values of the control group. All data are the mean ± SD. ∗P < 0.05 compared with control group, #P < 0.05 compared with I/R group.

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  FIGURE 4. Eriodictyol treatment elevates the JAK2 activation. (A) The protein levels of JAK2, p-JAK2, STAT3, and p-STAT3 in cardiac tissues were measured by western blot. Statistical analysis of p-JAK2/JAK2 ratio (B) and p-STAT3/STAT3 ratio (C) in cardiac tissues. n = 4 per group. The protein ratios were normalized to the values of the control group. All data are the mean ± SD. ∗P < 0.05 compared with control group, #P < 0.05 compared with I/R group.

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  FIGURE 5. JAK2 specific inhibitor AG490 abolishes the protective effect of EDT in myocardium I/R injury. The values of LVDP (A), +dP/dtmax (B), -dP/dtmax (C), and CF (D) in rat hearts were measured after co-treatment with EDT and AG490. The values of these parameters were normalized to the values of the recorded data before 15 min of zero-flow global ischemia. The levels of LDH (E) and CK (F) in K–H buffer were determined after co-treatment with EDT and AG490. (G) The infarct size was examined by TTC staining after co-treatment with EDT and AG490. Scale bar: 1 mm. n = 8 for each group. All data are the mean ± SD. ∗P < 0.05, ∗∗P < 0.01.

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  FIGURE 6. AG490 abolishes the effect of EDT on inflammatory response and cardiomyocyte apoptosis in global myocardial I/R. The effect of EDT on IL-6 (A), CRP (B), IL-8 (C), and TNF-α (D) levels in cardiac tissues were measured after co-treatment with AG490. (E) The cardiomyocyte apoptosis in cardiac tissues was examined after co-treatment with EDT and AG490. Brown staining of the nucleus indicates cell apoptosis. Scale bar: 20 μm. n = 8 for each group. All data are the mean ± SD. ∗P < 0.05, ∗∗P < 0.01.

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  FIGURE 7. AG490 abolishes the effect of EDT on the expression of apoptosis-related proteins and the activation of JAK2 in myocardium I/R injury. (A) The protein levels of Bax, Bcl-2 and cleaved Caspase-3 in cardiac tissues were measured by western blot. (B) Statistical analysis of Bax, Bcl-2 and cleaved Caspase-3 protein levels in cardiac tissues from the indicated groups. (C) The protein levels of JAK2, p-JAK2, STAT3, and p-STAT3 in cardiac tissues were measured by western blot. (D) Statistical analysis of p-JAK2/JAK2 ratio and p-STAT3/STAT3 ratio in cardiac tissues from the indicated groups. n = 4 per group. The protein ratios were normalized to the values of the control group. All data are the mean ± SD. ∗P < 0.05.