Dose-Dependent Effects of Long-Term Administration of Hydrogen Sulfide on Myocardial Ischemia–Reperfusion Injury in Male Wistar Rats: Modulation of RKIP, NF-κB, and Oxidative Stress

Figures

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  Figure 1. Dose-dependent effects of NaSH on systolic blood pressure (SBP) (A) and heart rate (B). Values are mean ± SEM (n = 6/group); * p < 0.05 compared to non-treated control rats.

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  Figure 2. Effects of different doses of NaSH on hemodynamic parameters during the stabilization period. Hemodynamic parameters included left ventricular developed pressure (LVDP, A); peak rate of positive changes in left ventricular pressure (+dp/dt, B); peak rate of negative changes in left ventricular pressure (−dp/dt, C); and heart rate (HR, D). Values are mean ± SEM (n = 6/group); * p < 0.05 compared to non-treated control rats.

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  Figure 3. Effects of different doses of NaSH on hemodynamic parameters during the recovery period. Hemodynamic parameters included left ventricular developed pressure (LVDP, A); peak rate of positive changes in left ventricular pressure (+dp/dt, B); peak rate of negative changes in left ventricular pressure (−dp/dt, C) and heart rate (HR, D). Values are mean ± SEM (n = 6/group); * p < 0.05 compared to non-treated control rats.

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  Figure 4. Effects of different doses of NaSH on heart hydrogen sulfide (H2S, A) and nitrite + nitrate (NOx, B) levels after the ischemia–reperfusion (IR) period. Values are mean ± SEM; (n = 6/group); * p < 0.05 compared to non-treated rats.

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  Figure 5. Effects of different doses of NaSH on infarct sizes. Values are mean ± SEM; (n = 6/group); * p < 0.05 compared to non-treated control rats.

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  Figure 6. Effect of NaSH on mRNA expression of H2S- and NO-producing enzymes in heart tissue. H2S-producing enzymes including cystathionine gamma-lyase (CSE, A), cystathionine-β-synthase (CBS, B), and mercaptopyruvate sulfurtransferase (3-MST, C) and NO-producing enzymes including inducible nitric oxide synthase (iNOS, D), endothelial nitric oxide synthase (eNOS, E), and neuronal nitric oxide synthase (nNOS, F). Values are mean ± SEM; (n = 6/group); * p < 0.05 compared to non-treated control rats.

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  Figure 7. Effect of NaSH on mRNA expression of Raf kinase inhibitor protein (RKIP, A) and nuclear factor kappa-B (NF-κB, B) in heart tissue. Values are mean ± SEM; (n = 6/group); * p < 0.05 compared to non-treated control rats.

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  Figure 8. Effects of NaSH administration on oxidative stress indices of heart tissue. Oxidative stress indices including malondialdehyde (MDA, A), catalase activity (CAT, B), total antioxidant capacity (TAC, C), and reduced glutathione-to-oxidized-glutathione ratio (GSH/GSSG, D). Values are mean ± SEM; (n = 6/group); * p < 0.05 compared to non-treated control rats.

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  Figure 9. Experimental protocol and the timeline of the study. NaSH at 0.28, 0.56, 1.6, 2.8, and 5.6 mg/kg/day was administrated for a period of 9 weeks as detailed in Section 2.2. NaSH, sodium hydrosulfide; H2S, hydrogen sulfide; CBS, cystathionine β-synthase; CSE, cystathionine γ-lyase; 3-MST, 3-mercaptopyruvate sulfurtransferase; NOS, nitric oxide synthase; nNOS, neuronal NOS; eNOS, endothelial NOS; iNOS, inducible NOS; RKIP, Raf kinase inhibitor protein; NF-κB, nuclear factor kappa-B.

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  Figure 10. Proposed mechanism for the protective and detrimental effects of NaSH against myocardial IR injury in normal rat. Solid and dashed arrows indicate effect of NaSH administration at 1.6 mg/kg and 5.6 mg/kg, respectively. Standard arrows indicate upregulation while flat-headed arrows indicate downregulation. CSE, cystathionine γ-lyase; CBS, cystathionine β-synthase; 3-MST, 3-mercaptopyruvate sulfurtransferase; NOS, nitric oxide synthase; nNOS, neuronal NOS; eNOS, endothelial NOS; iNOS, inducible NOS; RKIP, Raf kinase inhibitor protein; NF-κB, nuclear factor kappa-B.