Cardioprotective Effects of Malvidin Against Isoproterenol-Induced Myocardial Infarction in Rats: A Mechanistic Study

Abstract

BACKGROUND Malvidin (alvidin-3-glucoside) is a polyphenol that belongs to the class of natural anthocyanin, which is abundantly found in red wines, colored fruits, and the skin of red grapes. Therefore, the current investigation was intended to evaluate the effect of malvidin against myocardial infarction induced by isoproterenol in the rats. MATERIAL AND METHODS The cardioprotective effects was assessed by determining the effect of malvidin on the activities of endogenous antioxidants - catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH) - and on the levels of lipid peroxidation and serum marker enzymes. The serum levels of IL-6 and TNF-α were also determined using an enzyme-linked immunosorbent assay (ELISA) kit. RESULTS The present study demonstrated a significant cardioprotective effect of malvidin by restoring the defensive activities of endogenous antioxidants - catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH) - and by reducing the levels of lipid peroxidation and serum marker enzymes lactate dehydrogenase (LD) and creatine kinase (CK). Malvidin significantly ameliorated the histopathological changes and impaired mitochondria in the cardiac necrosis stimulated with isoproterenol. Additionally, the results also demonstrated that nuclear translocation of Nrf-2 and subsequent HO-1 expression might be associated with nuclear factor kappa B (NF-κB) pathway activation. CONCLUSIONS Our findings suggest that malvidin exerts cardioprotective effects that might be due to possible strong antioxidant and anti-inflammatory activities. Therefore, this study provides the basis for the development of malvidin as a safe and effective treatment of myocardial infarction.

Figure 1

Effects of malvidin on myocardial injury marker enzymes in ISP-induced MI in rats. (A) Level of lactate dehydrogenase (LD) and (B) level of creatinine kinase (CK) were measured in serum. Values are presented as mean ±S.E.M. ^a p<0.05, ^d p>0.05, compared to saline control (normal control); ^c p<0.05, ^b p>0.05, compared to ISP control. ISP – isoproterenol; Malv – malvidin; LD – lactate dehydrogenase; CK – creatinine kinase.

Figure 2

Effects of malvidin on antioxidant enzymes in ISP-induced MI in rats. The levels of antioxidants were measured in the heart of rats. Values are presented as mean ±S.E.M. ^a p<0.05, ^c p>0.05, compared to saline control (normal control); ^b p<0.05, compared to ISP control. ISP – isoproterenoll Malv – malvidin; MDA – malondialdehyde; SOD – superoxide dismutase; CAT – catalase; GSH – glutathione.

Figure 3

Effect of malvidin on mitochondrial enzyme complex 1, 2, 3, and 4 in heart. The levels of mitochondrial enzyme complex 1, 2, 3, and 4 were measured in the hearts of rats. Values are presented as mean ±S.E.M. ^a p<0.05, ^c p>0.05, compared to saline control (normal control); ^b p<0.05, compared to ISP control. ISP – isoproterenol; Malv – malvidin; Mitochondrial enzymes (complex1 – NADH dehydrogenase, complex2 – succinate dehydrogenase, complex3 – MTT ability, and complex-4 – cytochrome-c oxidase).

Figure 4

Effect of malvidin on the serum level of pro-inflammatory cytokines IL-6 (A) and TNF-α (B) in ISO-induced myocardial infarction in rats. Values are expressed as means ±S.E.M. Compared with control: ^# P<0.05; ^## P<0.01; ^### P<0.001; Compared with model: * P<0.05; ** P<0.01; *** P<0.001.

Figure 5

Effect of malvidin treatment on histopathological changes in myocardium (cardiac tissue light micrograph at magnification 100×). (A) Saline control (normal control) rats showed clearly normal histoarchitecture of the myocardium; (B) ISP (85 mg/kg) control group presented moderate-to-marked myocardium necrosis, edema, and infiltration of inflammatory cells; (C) Malvidin (100 mg/kg) group presented moderate myocardium necrosis with lesser edema and infiltration of inflammatory cells compared to the ISP control group; (D) The malvidin (200 mg/kg) group presented mild myocardial necrosis with a significant decrease in edema and infiltration of inflammatory cells compared to the ISP control group; (E) The enalapril (10 mg/kg) group presented mild necrosis with a significant decrease in edema and focal infiltration of inflammatory cells compared to the ISP control group; (F) The malvidin (200 mg/kg) alone group presented similar histoarchitecture of myocardium as in the saline control (normal control) rats.

Figure 6

Effect of malvidin treatments significantly increased HO-1 induction and activated nuclear respiratory factor 2 (Nrf-2) translocation in ISO-induced myocardial infarction in rats. Representative immunoblots for HO-1 and Nrf-2.

Figure 7

Effect of malvidin on IκB-α and NF-κB phosphorylation determined by Western blot analysis.