Antioxidant and cardioprotective effects of Ilex cornuta on myocardial ischemia injury

Ameliorative Effects of Ponicidin Against the Isoproterenol-induced Acute Myocardial Infarction in Rats

Background

Cardiovascular disease (CVD) is a group of heart disorders, which is a major cause of noncommunicable disease-related mortalities worldwide. Myocardial infarction (MI) is an acute disorder due to the poor supply of oxygen and blood to the myocardium. MI is the foremost form of CVD, which is the primary cause of mortality worldwide.

Objectives

Here, we intended to discover the ameliorative properties of the ponicidin against the isoproterenol (ISO)-stimulated MI in rats.

Methodology

About 85 mg/kg of ISO was administered to the rats to trigger the MI and then treated with 25 and 50 mg/kg of ponicidin. The body weight and heart weight of all rats were determined. The total protein, c-reactive protein (CRP), and uric acid levels were examined. The activities of cardiac function markers such as creatine kinase (CK), ALT, AST, and gamma-glutamyl transferase (GGT) were examined. The antioxidants such as glutathione (GSH), GST, and GPx were examined by the previous methods. The status of Na+/K+, Mg2+, and Ca2+ ATPase activities was assessed using kits. The status of Na+, K+, and Ca2+ ions and inflammatory makers such as TNF-α and IL-6 were investigated using respective kits. The histopathological analysis was performed on the heart tissues to detect the histological changes.

Results

The results revealed that ponicidin increased body weight and decreased heart weight in MI rats. The status of CRP and uric acid was decreased and total protein was augmented in the ponicidin-treated MI rats. The AST, ALT, CK, and GGT activities were appreciably decreased in serum and elevated in the cardiac tissues of the ponicidin-administered MI rats. Furthermore, the ponicidin improved the antioxidant levels, decreased the TNF-α and IL-6, and regulated the Na+, K+, and Ca2+ ion transports in the MI rats. The activities of Na+/K+, Mg2+, and Ca2+ ATPase enzymes were remarkably increased in the heart tissues by the ponicidin-treated MI rats. Ponicidin treatment also ameliorated the ISO-stimulated histological alterations in the heart tissue of the MI rats.

Conclusion

Ponicidin treatment appreciably improved the antioxidants, Na+/K+, Mg2+, and Ca2+ ATPase enzyme activities, decreased the inflammatory markers, and regulated the cardiac marker enzyme activities in the MI rats. Hence, it can be a talented therapeutic candidate in the future to treat MI.

Cardioprotection Attributed to Aerobic Exercise-Mediated Inhibition of ALCAT1 and Oxidative Stress-Induced Apoptosis in MI Rats

Cardiolipin (CL) plays a pivotal role in mitochondria-mediated apoptosis. Acyl-CoA: lysocardiolipin acyltransferase 1 (ALCAT1) can accelerate CL reactive oxygen production and cause mitochondrial damage. Although we have demonstrated that aerobic exercise significantly reduced ALCAT1 levels in MI mice, what is the temporal characteristic of ALCAT1 after MI? Little is known. Based on this, the effect of exercise on ALCAT1 in MI rats needs to be further verified. Therefore, this paper aimed to characterize ALCAT1 expression, and investigate the possible impact of exercise on ALCAT1 and its role in fibrosis, antioxidant capacity, and apoptosis in MI rats. Our results indicated that the potential utility of MI increased ALCAT1 expression within 1–6 h of MI, and serum CK and CKMB had significant effects in MI at 24 h, while LDH exerted an effect five days after MI. Furthermore, ALCAT1 expression was upregulated, oxidative capacity and excessive apoptosis were enhanced, and cardiac function was decreased after MI, and aerobic exercise can reverse these changes. These findings revealed a previously unknown endogenous cardiac injury factor, ALCAT1, and demonstrated that ALCAT1 damaged the heart of MI rats, and aerobic exercise reduced ALCAT1 expression, oxidative stress, and apoptosis after MI-induced cardiac injury in rats.

The cardioprotective effects of the new crystal form of puerarin in isoproterenol-induced myocardial ischemia rats based on metabolomics

Puerarin has shown unique pharmacological effects on myocardial ischemia (MI). Changing the crystal form is an effective approach to improve the cardioprotective effects of puerarin. However, the mechanisms of the new crystal form of puerarin are unclear. In this study, an electrocardiogram, echocardiography, cardiac marker enzymatic activity, oxidative stress indices, and myocardial histology analysis of cardiac tissues were performed to evaluate the cardioprotective effects of the new crystal form of puerarin. Moreover, serum and cardiac tissue metabolomics based on nuclear magnetic resonance (NMR) were used to investigate the potential mechanism of the new crystal form. The results indicated that the new crystal form of puerarin (30 mg/kg) could improve oxidative stress indices, and these improvements were similar to those of the original crystal form of puerarin (120 mg/kg). The new crystal form of puerarin (30 mg/kg) could effectively improve the activities of cardiac marker enzymes, and the improvement effects were better than those of the original crystal form (120 mg/kg). Moreover, metabolomics analysis showed that amino acid metabolism, oxidative stress and energy metabolism were disturbed after MI and could be improved by puerarin. These results demonstrated that the new crystal form of puerarin was effective in treating MI.

Protective effects of five compounds from Livistona chinensis R. Brown leaves against hypoxia/reoxygenation, H2O2, or adriamycin-induced injury in H9c2 cells

Purpose: Discovering new antimyocardial ischemia drug candidates that are highly efficient, have low toxicity, and originate from natural products is a popular trend for new cardiovascular drug development at present. The ethanol extract of Livistona chinensis leaves showed a favorable antioxidant activity in our preliminary screening test. This study aims to screen out antioxidants from the herb leaves further and evaluate their efficacy in acute myocardial ischemia treatment at the cellular level. Materials and methods: Guided with online 1, 1-diphenyl-2-picrylhydrazyl (DPPH)-high-performance liquid chromatography (HPLC) screening, antioxidants were first separated and isolated from the ethanol extract of L. chinensis leaves by preparative-HPLC. Subsequently, offline DPPH approach was used to validate the free radical scavenging activity of the components. Ultimately, the resulting antioxidants were evaluated against the hypoxia/reoxygenation (H/R)-, H2O2-, or adriamycin (ADM)-induced injury in H9c2 cells to verify their cardioprotective effects in vitro. Results: Five antioxidant ingredients, namely, orientin, isoorientin, vitexin, isovitexin, and tricin, were quickly distinguished and isolated from L. chinensis leaves. The IC50 values of these ingredients were further examined by offline DPPH assay, as follows: 15.51±0.22, 6.64±0.38, 11.86±0.24, 8.89±0.66, and 31.86±0.24 μg/mL, respectively. Out of these ingredients, isoorientin showed the strongest antioxidation, which was equivalent to that of the positive control drug (vitamin C, IC50: 6.99±0.62 μg/mL). Using H/R-, H2O2-, and ADM-induced H9c2 cell injury models, the five ingredients had different extents of cardioprotective effects in vitro. In particular, isoorientin showed the strongest protection. All the five ingredients also showed insignificant cytotoxic effect to normal H9c2 cells. Conclusion: The ethanol extract of L. chinensis leaves contained five antioxidants with low cardiac cytotoxicity. Isoorientin possessed the strongest antioxidation, which can predominantly account for the myocardial protection effects within the extract.

Vitamin C and sodium bicarbonate enhance the antioxidant ability of H9C2 cells and induce HSPs to relieve heat stress

Heat stress is exacerbated by global warming and affects human and animal health, leading to heart damage caused by imbalances in reactive oxygen species (ROS) and the antioxidant system, acid-base chemistry, electrolytes and respiratory alkalosis. Vitamin C scavenges excess ROS, and sodium bicarbonate maintains acid-base and electrolyte balance, and alleviates respiratory alkalosis. Herein, we explored the ability of vitamin C alone and in combination with equimolar sodium bicarbonate (Vitamin C-Na) to stimulate endogenous antioxidants and heat shock proteins (HSPs) to relieve heat stress in H9C2 cells. Control, vitamin C (20 μg/ml vitamin C for 16 h) and vitamin C-Na (20 μg/ml vitamin C-Na for 16 h) groups were heat-stressed for 1, 3 or 5 h. Granular and vacuolar degeneration, karyopyknosis and damage to nuclei and mitochondria were clearly reduced in treatment groups, as were apoptosis, lactate dehydrogenase activity and ROS and malondialdehyde levels, while superoxide dismutase activity was increased. Additionally, CRYAB, Hsp27, Hsp60 and Hsp70 mRNA levels were upregulated at 3 h (p < 0.01), and protein levels were increased for CRYAB at 0 h (p < 0.05) and 1 h (p < 0.01), and for Hsp70 at 3 and 5 h (p < 0.01). Thus, pre-treatment with vitamin C or vitamin C-Na might protect H9C2 cells against heat damage by enhancing the antioxidant ability and upregulating CRYAB and Hsp70.

MicroRNA-126a-5p enhances myocardial ischemia-reperfusion injury through suppressing Hspb8 expression

Previously, we found several genes are involved in myocardial ischemia-reperfusion (M-I/R) injury. In this report, we first developed a mouse model of M-I/R injury and demonstrated microRNA-126a-5p was associated with the M-I/R injury by using high-throughput microRNA expression analysis. We further investigated the expression and function of microRNA-126a-5p during mouse M-I/R injury. We observed high expression of microRNA-126a-5p in the M-I/R mice and increased levels of LDH and CK-MB (damage markers) in the serum. H₂O₂ and hypoxia/reoxygenation (H/R) treatment significantly increased the expression of microRNA-126a-5p in H9C2 cells in concentration- and time-dependent manners. Moreover, microRNA-126a-5p overexpression in H9C2 cells inhibited cell viability but increased LDH release and caspase 3 activity. Cardiac function analysis based on the measurements of hemodynamic parameters showed that microRNA-126a-5p expression ablation in M-I/R injured mice led to the reversal of the symptoms caused by M-I/R injury. Transesophageal echocardiography also revealed that the values of LVIDd and LVIDs were decreased while the values of LVFS% and LVEF% were increased in M-I/R injured mice after treatment with microRNA-126a-5p inhibitor, compared with the M-I/R injured mice treated with the control. Bioinformatic analysis demonstrated that Hspb8, a protective protein in myocardium, was the target of microRNA-126a-5p. Thus, these findings indicated that microRNA-126a-5p was up-regulated in mouse M-I/R model and promoted M-I/R injury in vivo through suppressing the expression of Hspb8, which may shed light on the development of potential therapeutic target for M-I/R injury.