Punicalagin attenuates myocardial oxidative damage, inflammation, and apoptosis in isoproterenol-induced myocardial infarction in rats: Biochemical, immunohistochemical, and in silico molecular docking studies.

Myocardial infarction (MI) is a life-threatening ischemic disease and is one of the leading causes of morbidity and mortality worldwide. Punicalagin (PU), the major ellagitannin found in pomegranates, is characterized by multiple antioxidant activities. The aim of this study is to assess the protective effects of PU against isoproterenol (ISO)-induced acute myocardial damage and to investigate its underlying vascular mechanisms using rat model. METHODS: Rats were randomly divided into five groups and were treated orally (p.o.) with PU (25 and 50 mg/kg) for 14 days. ISO was administered subcutaneously (S.C.) (85 mg/kg) on the 15th and 16th days to induce Myocardial infarction. Cardiac markers, oxidative stress markers, and inflammatory cytokines levels were determined in the heart tissue. Immunohistochemistry analysis was performed to determine the protein expression pathways of inflammation, apoptosis and oxidative stress (Nuclear factor erythroid 2-related factor 2 (Nrf-2), and heme oxygenase-1 (HO-1) in all the groups. In silico study was carried out to evaluate the molecular interaction of PU with some molecular targets. RESULTS: Our results showed that ISO-induced cardiac tissue injury was evidenced by increased serum creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), and lactate dehydrogenase (LDH), associated with several histopathological changes. ISO also induced an increase of MDA, PCO, NO, and 8-hydroxy-2-deoxyguanosine (8-OHdG), along with a decrease of antioxidant enzyme activities in the myocardial tissues. In addition, an increase of TNF-α, NF-κB, IL-6, IL-1β, iNOS, Nrf2 and (HO-1) was observed. Pre-treatment with PU reduced myocardial infract area, ameliorated histopathological alterations in myocardium, and decreased activities of myocardial injury marker enzymes in ISO-induced rats. In addition, PU remarkably restored ISO-induced elevation of lipid peroxidation and decrease of antioxidants, significantly reduced myocardial pro-inflammatory cytokines concentrations in this animal model. Molecular docking analysis of PU with protein targets showed potent interactions with negative binding energies. In conclusion, PU can protect the myocardium from oxidative injury, inflammatory response, and cell death induced by ISO by upregulating Nrf2/HO-1 signaling and antioxidants.