Apigenin Protects Against Cisplatin-Induced Cardiotoxicity: Potential Involvement of CD38-Sirt3 Signaling in Rats

Figures

• 

  Figure 1. Effects of cisplatin (5 mg/kg) and apigenin pretreatment (50 mg/kg) on LV function in cisplatin-induced cardiotoxicity. (A) %LVEF, n = 8 per group; (B) %LVFS, n = 8 per group; and (C) M-mode echocardiographic images. * p < 0.05 vs. Con and † p < 0.05 vs. Cis (one-way ANOVA followed by Tukey’s post hoc test). Data were expressed as mean ± S.E.M. Con: rats treated with vehicle; Cis: rats treated with cisplatin at 5 mg/kg; Api + Cis: rats pretreated with apigenin at 50 mg/kg plus cisplatin 5 mg/kg; LVEF: left ventricular ejection fraction; and LVFS: left ventricular fractional shortening.

• 

  Figure 2. Effects of cisplatin (5 mg/kg) and apigenin pretreatment (50 mg/kg) on cardiac injury and cardiac oxidative stress status in cisplatin-induced cardiotoxicity. (A) plasma LDH levels, n = 8 per group; (B) plasma CK-MB levels, n = 8 per group; (C) cardiac MDA levels, n = 8 per group; and (D) cardiac GSH levels, n = 8 per group. * p < 0.05 vs. Con and † p < 0.05 vs. Cis (one-way ANOVA followed by Tukey’s post hoc test). Data were expressed as mean ± S.E.M. Con: rats treated with vehicle; Cis: rats treated with cisplatin at 5 mg/kg; Api + Cis: rats pretreated with apigenin at 50 mg/kg plus cisplatin 5 mg/kg; LDH: lactate dehydrogenase; CK-MB: creatine kinase-myocardial band; MDA: malondialdehyde; GSH: glutathione.

• 

  Figure 3. Effects of cisplatin (5 mg/kg) and apigenin pretreatment (50 mg/kg) on cardiac oxidative stress-related proteins in cisplatin-induced cardiotoxicity. (A) cardiac CD38 levels, n = 8 per group; (B) cardiac Sirt3 levels, n = 8 per group; (C) cardiac SOD2 levels, n = 8 per group; (D) cardiac ac-SOD2 levels, n = 8 per group; and (E) representative Western blots. GAPDH was used as a loading control. * p < 0.05 vs. Con and † p < 0.05 vs. Cis (one-way ANOVA followed by Tukey’s post hoc test). Data were expressed as mean ± S.E.M. Con: rats treated with vehicle; Cis: rats treated with cisplatin at 5 mg/kg; Api + Cis: rats pretreated with apigenin at 50 mg/kg plus cisplatin 5 mg/kg; CD38: cluster of differentiation 38; Sirt3: sirtuin 3; SOD2: superoxide dismutase 2; ac-SOD2: acetylated superoxide dismutase 2 at lysine 68; and GAPDH: glyceraldehyde 3-phosphate dehydrogenase.

• 

  Figure 4. Effects of cisplatin (5 mg/kg) and apigenin pretreatment (50 mg/kg) on cardiac inflammatory responses in cisplatin-induced cardiotoxicity. (A) cardiac TNF-α levels, n = 8 per group; (B) cardiac IL-1β levels, n = 8 per group; (C) cardiac TLR-4 levels, n = 8 per group; (D) cardiac p-NF-κB levels, n = 8 per group; and (E) representative Western blots. GAPDH was used as a loading control. * p < 0.05 vs. Con and † p < 0.05 vs. Cis (one-way ANOVA followed by Tukey’s post hoc test). Data were expressed as mean ± S.E.M. Con: rats treated with vehicle; Cis: rats treated with cisplatin at 5 mg/kg; Api + Cis: rats pretreated with apigenin at 50 mg/kg plus cisplatin 5 mg/kg; TNF-α: tumor necrosis factor alpha; IL-1β: interleukin-1 beta; TLR-4: toll-like receptor 4; p-NF-κB: phosphorylation of nuclear factor kappa-light-chain-enhancer of activated B cells; and GAPDH: glyceraldehyde 3-phosphate dehydrogenase.

• 

  Figure 5. Representative images of cardiac tissue stained with H&E showing the effects of cisplatin at 5 mg/kg and pretreatment with apigenin at 50 mg/kg on histopathological changes at 100× magnification. Black arrows indicate inflammatory cell infiltration in cardiac tissue. Con: rats treated with vehicle; Cis: rats treated with cisplatin at 5 mg/kg; Api + Cis: rats pretreated with apigenin at 50 mg/kg plus cisplatin 5 mg/kg; and H&E: hematoxylin and eosin.

• 

  Figure 6. Effects of cisplatin (5 mg/kg) and apigenin pretreatment (50 mg/kg) on cardiac apoptosis in cisplatin-induced cardiotoxicty. (A) cardiac Bax/Bcl-2 levels, n = 8 per group; (B) cardiac cleaved caspase-3/procaspase-3 levels, n = 8 per group; and (C) representative Western blots. GAPDH was used as a loading control. * p < 0.05 vs. Con and † p < 0.05 vs. Cis (one-way ANOVA followed by Tukey’s post hoc test). Data were expressed as mean ± S.E.M. Con: rats treated with vehicle; Cis: rats treated with cisplatin at 5 mg/kg; Api + Cis: rats pretreated with apigenin at 50 mg/kg plus cisplatin 5 mg/kg; Bax: Bcl-2-associated X; Bcl-2: B-cell lymphoma 2; and GAPDH: glyceraldehyde 3-phosphate dehydrogenase.

• 

  Figure 7. Proposed mechanism underlying the cardioprotective effects of apigenin against cisplatin-induced cardiotoxicity in rats. ac-SOD2: acetylated superoxide dismutase 2 at lysine 68; Api: apigenin; Bax: Bcl-2-associated X; Bcl-2: B-cell lymphoma 2; CD38: cluster of differentiation 38; Cis: cisplatin; CK-MB: creatine kinase-myocardial band; EF: ejection fraction; FS: fractional shortening; GSH: glutathione; i.p.: intraperitoneal injection; IL-1β: interleukin-1 beta; LDH: lactate dehydrogenase; LV: left ventricular; MDA: malondialdehyde; NF-κB: nuclear factor kappa-light-chain-enhancer of activated B cells; p.o.: oral gavage; Sirt3: sirtuin 3; SOD2: superoxide dismutase 2; TLR-4: toll-like receptor 4; TNF-α: tumor necrosis factor alpha.

• 

  Figure 8. Schematic illustration of the experimental protocol. p.o.: oral gavage; i.p.: intraperitoneal injection; NSS: normal saline solution; LVEF: left ventricular ejection fraction; and LVFS: left ventricular fractional shortening.