Activated ROCK/Akt/eNOS and ET-1/ERK pathways in 5-fluorouracil-induced cardiotoxicity: modulation by simvastatin

Figures

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  Figure 1. ECG recording from (A) Normal control, (B) Sim-treated, (C, D) 5-FU-treated and (E) 5-FU + Sim treated groups. ECG shows normal pattern, except in panels (C, D), which clearly show elevation in the ST segment (red arrow). 5-FU 5-fluorouracil, Sim simvastatin.

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  Figure 2. Effect of 5-FU and Sim treatments on serum levels of (A) NT-proBNP and (B) cTnI. Values are presented as the mean of 6–8 experiments ± SEM. Statistical analysis was done using one-way ANOVA followed by Tukey’s post-hoc test; as compared to normal (*), Sim (#), and 5-FU (@)-treated groups (p < 0.05). 5-FU 5-fluorouracil, cTnI cardiac troponin I, NT-proBNP N-terminal pro-brain natriuretic peptide, Sim simvastatin.

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  Figure 3. Effect of 5-FU and Sim treatments on aortic tissue contents of (A) ET-1 and (B) TXA2. Values are presented as the mean of 6 experiments ± SEM. Statistical analysis was done using one-way ANOVA followed by Tukey’s post-hoc test; as compared to normal (*), Sim (#), and 5-FU (@)-treated groups (p < 0.05). 5-FU 5-fluorouracil, ET-1 endothelin-1, Sim simvastatin, TXA2 thromboxane A2.

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  Figure 4. Effect of 5-FU and Sim treatments on cardiac (A) content of p-ERK, (B) expression of ROCK, (C) expression and (D) activity of caspase-3 and (E) DNA fragmentation analysis, in which 5-FU group shows DNA laddering. Values are presented as the mean of 6–8 experiments ± SEM. Statistical analysis was carried out using one-way ANOVA followed by Tukey’s post-hoc test; as compared to normal (*), Sim (#), and 5-FU (@)-treated groups (p < 0.05). 5-FU 5-fluorouracil, M, marker DNA (1 kb), p-ERK1/2 (Thr202/Tyr204), phosphorylated extracellular signal-regulated kinase 1/2 at Thr 202 & Tyr 204, ROCK rho-kinase, Sim simvastatin.

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  Figure 5. Effect of 5-FU and Sim co-treatment on cardiac tissue contents of (A) Nox, (B) MDA, (C) GSH, (D) COX-2 and (E) p-NF-κB p65. Values are presented as the mean of 6–8 experiments ± SEM. Statistical analysis was carried out using one-way ANOVA followed by Tukey’s post-hoc test; as compared to normal (*), Sim (#), and 5-FU (@)-treated groups (p < 0.05). 5-FU 5-fluorouracil, COX-2 cyclooxygenase-2, GSH glutathione reduced form, MDA malondialdehyde, p-NF-κB p65 (Ser536) phosphorylated nuclear factor-kappa B p65 at Ser 536, Nox NADPH-oxidase, Sim simvastatin.

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  Figure 6. Effect of 5-FU and Sim treatments on cardiac tissue contents of (A) p-Akt and (B) p-eNOS. Values are presented as the mean of 6–7 experiments ± SEM. Statistical analysis was carried out using one-way ANOVA followed by Tukey’s post-hoc test; as compared to normal (*), Sim (#), and 5-FU (@)-treated groups (p < 0.05). 5-FU 5-fluorouracil, p-Akt (Ser473) phosphorylated protein kinase B at Ser 473, p-eNOS (Ser1177) phosphorylated endothelial nitric oxide synthase at Ser 1177, p-ERK1/2 (Thr202/Tyr204) phosphorylated extracellular signal-regulated kinase 1/2 at Thr 202 & Tyr 204, Sim simvastatin.

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  Figure 7. Effect of Sim on 5-FU-induced histological changes in cardiomyocytes. Photomicrographs (A–D) represent specimens taken from the heart and changes are indicated in the panel by black arrows. Slides of (A) normal control group and (B) normal animals treated with Sim show unremarkable changes, while that from (C1) 5-FU group shows intermuscular inflammatory cells infiltration associated with edema. Additionally, (C2, C3) slides from 5-FU group show focal necrosis of cardiomyocytes associated with congestion of myocardial blood vessel, as well as vacuolization of the sarcoplasm of cardiomyocytes. However, slide from animals treated with (D) 5-FU + Sim shows no histopathological changes. 5-FU 5-flourouracil, Sim simvastatin (H&E × 400; scale bar: 20 µm).

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  Figure 8. Effect of Sim on 5-FU-induced histological changes in aortic tissue. Photomicrographs from a-d represent specimens taken from the aorta. Sections from (a) normal control group and that (b) treated with Sim, show normal histological layers with no histopathological changes. On the contrary, sections of (c1–c3) 5-FU treated animals show vacuolation of cells of tunica media, whereas section (d) from 5-FU + Sim group shows no histopathological changes. 5-FU 5-flourouracil; Sim simvastatin (H&E × 400; scale bar: 20 µm).