Spironolactone Protects against Diabetic Cardiomyopathy in Streptozotocin-Induced Diabetic Rats

Figures

• 

  Figure 1. Cardiac ultramicrostructure was preserved in SPR-treated rats. (a–c) Representative electron micrographs for mitochondria, myofibrils, and sarcoplasmic reticulum, respectively. In the NDC group, normal ultrastructure was observed in the heart tissue. Loss of cristae, irregular arrangement of myofibrils, and enlarged sarcoplasmic reticula were observed in the STZ + NS group. Pathological changes in the STZ + SPR group were significantly reduced compared to those of the diabetic group. Red, blue, and green arrows indicate mitochondria, myofibrils, and sarcoplasmic reticulum, respectively.

• 

  Figure 2. SPR abolished myocardial oxidative stress in diabetic rats. (a) Representative immunohistochemical (IHC) micrographs of myocardium tissue from NDC, STZ + NS, and STZ + SPR groups stained with nitrotyrosine. Magnification 20×. (b) Immunohistochemical scores for the IHC staining of myocardium sections. (c, d) Gene expression of Nrf-1 and GCLC for these three groups. N = 8, data are shown as means ± SEM. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001 vs. NDC group; #P < 0.05 and ###P < 0.001 vs. STZ + NS group.

• 

  Figure 3. SPR protected against myocardial hypertrophy and fibrosis in DCM. (a) Representative images of cardiac tissue stained with HE (transsection) for NDC, STZ + NS, and STZ + SPR groups (original magnification 40×). (b) Representative images of cardiac tissue stained with HE (longisection) for NDC, STZ + NS, and STZ + SPR groups (original magnification 20×). (c) Representative electron micrographs for the extracellular matrix from NDC, STZ + NS, and STZ + SPR groups. Compared to the NDC group, the deposition of the extracellular matrix (ECM) tended to be increased in the STZ + NS group, while SPR treatment reduced this pathological change. Blue arrows indicate ECM. (d, e) Representative images of cardiac tissue stained with PAS and Masson for the NDC, STZ + NS, and STZ + SPR groups are presented (original magnification 20×). (f, e) Quantification results summarizing the cross-sectional diameter of myocytes within transverse cardiac sections. (g, h) Quantification results of the PAS and Masson staining positive area in cardiac sections of rats treated under the conditions indicated, respectively. N = 8 for each group, data are shown as means ± SEM. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P <…

• 

  Figure 4. SPR protected against myocardial hypertrophy and fibrosis in DCM. (a) Representative immunohistochemical micrographs of cardiac tissue stained with collagen 1 and TGF-β1 (original magnification 20×). (b) The IHC scores of heart sections for collagen 1 and TGF-β1 IHC staining. (c) The protein expression of collagen 1 and TGF-β1 examined by Western blot. (d) The quantification data of Western blot for collagen 1 and TGF-β1. (e) Gene expression of collagen 1 and TGF-β1 for these 3 groups. N = 8, data are shown as means ± SEM. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001 vs. NDC group; #P < 0.05, ##P < 0.01, and ###P < 0.001 vs. STZ + NS group.

• 

  Figure 5. SPR reduced cardiac inflammation in DCM. (a) Representative immunohistochemical micrographs of cardiac tissue stained with TNF-α and F4/80 for NDC, STZ + NS, and STZ + SPR groups, respectively (original magnification 20×). (b) The IHC scores of heart sections for TNF-α IHC staining. (c) The percentage of positive staining per section for F4/80 IHC staining. (d, e) Gene expression of TNF-α and MCP-1 for these three groups, respectively. N = 8, data are shown as means ± SEM. ∗P<0.05, ∗∗P<0.01, and ∗∗∗P<0.001 vs. NDC group; ##P < 0.01 and ###P < 0.001 vs. STZ + NS group.

• 

  Figure 6. SPR restored the mitochondria contents and improved myocardial energy metabolism in diabetic rats. (a–e) Gene expression of Eral1, ATP5α1, COX5b, Sirt1, and PGC-1α for NDC, STZ + NS, and STZ + SPR groups. N = 8, data are shown as means ± SEM. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001 vs. NDC group; #P < 0.05 and ##P < 0.01 vs. STZ + NS group.

• 

  Figure 7. SPR aborted the aggregated oxidative stress induced by aldosterone in a myocardioblast cell line. (a–c) Gene expression of GCLC, NRF-1, and Nox4 in H9C2 cells treated with aldosterone (10−7 mmol/L), with or without SPR (10−7 mol/L), for 72 h. (d) Cellular ROS levels after treatment with aldosterone, with or without SPR. N = 3, data are shown as mean ± SEM. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001 vs. control group; ##P < 0.01 and ###P < 0.001 vs. aldosterone-treated group.