Astragaloside IV attenuates apoptosis of hypertrophic cardiomyocyte through inhibiting oxidative stress and calpain-1 activation

Astragaloside IV inhibits angiotensin II-induced atrial fibrosis and atrial fibrillation by SIRT1/PGC-1α/FNDC5 pathway

Aims and objectives

Astragaloside IV (AS-IV) has been found to possess anti-oxidative, anti-inflammatory, and anti-apoptotic properties, but its effect on atrial fibrosis is yet to be determined. This research investigates the protective role of AS-IV in angiotensin II (Ang II)-induced atrial fibrosis and atrial fibrillation (AF).

Methods

C57BL/6 male mice aged 8-10 weeks (n = 40) were subcutaneously administered Ang II (2.0 mg/kg/day) or saline, with AS-IV (80 mg/kg) intraperitoneally administered 2 h before Ang II infusion for 4 weeks. Biochemical, histological, and morphological analyses were carried out. Using transesophageal burst pacing, AF was generated in vivo.

Results

Here, we report that AS-IV treatment inhibited Ang II-induced AF development in mice (58 ± 5.86 vs 15.13 ± 2.16 %, p < 0.001). Ang II + AS-IV therapy was effective in reducing the atrial fibrotic area and decreasing the increase in smooth muscle alpha-actin (α-SMA)-positive myofibroblasts brought on by Ang II treatment (fibrotic area: 26.25 ± 3.81 vs 8.62 ± 1.83 %, p < 0.001 and α-SMA: 65.62 ± 10.63 vs 17.25 ± 1.78 %, p < 0.001). The reactive oxygen species (ROS) production was reduced by pretreatment with Ang II + AS-IV (9.20 ± 0.92 vs 2.63 ± 0.22 %/sec, p < 0.001). In addition, Ang II + AS-IV treatment suppressed oxidative stress in Ang II-induced atrial fibrosis (malondialdehyde: 701.78 ± 85.01 vs 504.07 ± 25.62 pmol/mg protein, p < 0.001; superoxide dismutase: 13.82 ± 1.25 vs 29.54 ± 2.45 U/mg protein, p < 0.001 and catalase: 11.43 ± 1.19 vs 20.83 ± 3.29 U/mg protein, p < 0.001, respectively). Moreover, Ang II + AS-IV decreased the expression of α-SMA, collagen III and collagen I (3.32 ± 0.53 vs 1.41 ± 0.20 fold, p < 0.001; 3.41 ± 0.55 vs 1.48 ± 0.18 fold, p < 0.001; 2.34 ± 0.55 vs 0.99 ± 0.17 fold, p < 0.001, respectively) while increasing the protein expression of sirtuin 1 (SIRT1), peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α), and fibronectin type III domain-containing protein 5 (FNDC5) in Ang II-treated mice (0.22 ± 0.02 vs 0.57 ± 0.08 fold, p < 0.001; 0.28 ± 0.04 vs 0.72 ± 0.05 fold, p < 0.001; 0.38 ± 0.03 vs 0.68 ± 0.06 fold, p < 0.001, respectively).

Conclusion

Our data led us to speculate that AS-IV may protect against Ang II-induced atrial fibrosis and AF via upregulation of the SIRT1/PGC-1α/FNDC5 pathway.

A review of chemotherapeutic drugs-induced arrhythmia and potential intervention with traditional Chinese medicines

Significant advances in chemotherapy drugs have reduced mortality in patients with malignant tumors. However, chemotherapy-related cardiotoxicity increases the morbidity and mortality of patients, and has become the second leading cause of death after tumor recurrence, which has received more and more attention in recent years. Arrhythmia is one of the common types of chemotherapy-induced cardiotoxicity, and has become a new risk related to chemotherapy treatment, which seriously affects the therapeutic outcome in patients. Traditional Chinese medicine has experienced thousands of years of clinical practice in China, and has accumulated a wealth of medical theories and treatment formulas, which has unique advantages in the prevention and treatment of malignant diseases. Traditional Chinese medicine may reduce the arrhythmic toxicity caused by chemotherapy without affecting the anti-cancer effect. This paper mainly discussed the types and pathogenesis of secondary chemotherapeutic drug-induced arrhythmia (CDIA), and summarized the studies on Chinese medicine compounds, Chinese medicine Combination Formula and Chinese medicine injection that may be beneficial in intervention with secondary CDIA including atrial fibrillation, ventricular arrhythmia and sinus bradycardia, in order to provide reference for clinical prevention and treatment of chemotherapy-induced arrhythmias.

Astragaloside IV mitigates hypoxia-induced cardiac hypertrophy through calpain-1-mediated mTOR activation

BACKGROUND

Astragaloside IV (AsIV), a key functioning element of Astragalus membranaceus, has been recognized for its potential cardiovascular protective properties. However, there is a need to elucidate the impacts of AsIV on myocardial hypertrophy under hypoxia conditions and its root mechanisms.

PURPOSE

This study scrutinized the influence of AsIV on cardiac injury under hypoxia, with particular emphasis on the role of calpain-1 (CAPN1) in mediating mTOR pathways.

METHODS

Hypoxia-triggered cardiac hypertrophy was examined in vivo with CAPN1 knockout and wild-type C57BL/6 mice and in vitro with H9C2 cells. The impacts of AsIV, 3-methyladenine, and CAPN1 inhibition on hypertrophy, autophagy, apoptosis, [Ca2+]i, and CAPN1 and mTOR levels in cardiac tissues and H9C2 cells were investigated.

RESULTS

Both AsIV treatment and CAPN1 knockout mitigated hypoxia-induced cardiac hypertrophy, autophagy, and apoptosis in mice and H9C2 cells. Moreover, AsIV, 3-methyladenine, and CAPN1 inhibition augmented p-mTOR level but reduced [Ca2+]i and CAPN1 level. Additionally, lentivirus-mediated CAPN1 overexpression in H9C2 cells exacerbated myocardial hypertrophy, apoptosis, and p-mTOR inhibition under hypoxia. Specifically, AsIV treatment reversed the impacts of increased CAPN1 expression on cardiac injury and the inhibition of p-mTOR.

CONCLUSION

These findings suggest that AsIV may alleviate cardiac hypertrophy under hypoxia by attenuating apoptosis and autophagy through CAPN1-mediated mTOR activation.

The combination of Tanshinone IIA and Astragaloside IV attenuates myocardial ischemia-reperfusion injury by inhibiting the STING pathway

BACKGROUND

Astragaloside IV (As-IV) and Tanshinone IIA (Ta-IIA) are the main ingredients of traditional Chinese medicinal Astragalus membranaceus (Fisch.) Bunge and Salvia miltiorrhiza Bunge, respectively, both of which have been employed in the treatment of cardiovascular diseases. Nevertheless, the efficacy of the combination (Co) of Ta-IIA and As-IV for cardiovascular diseases remain unclear and warrant further investigation. This study aimed to investigate the efficacy and the underlying molecular mechanism of Co in treating myocardial ischemia-reperfusion injury (MIRI).

METHODS

In order to assess the efficacy of Co, an in vivo MIRI mouse model was created by temporarily blocking the coronary arteries for 30 min and then releasing the blockage. Parameters such as blood myocardial enzymes, infarct size, and ventricular function were measured. Additionally, in vitro experiments were conducted using HL1 cells in both hypoxia-reoxygenation model and oxidative stress models. The apoptosis rate, expression levels of apoptosis-related proteins, oxidative stress indexes, and release of inflammatory factors were detected. Furthermore, molecular docking was applied to examine the binding properties of Ta-IIA and As-IV to STING, and western blotting was performed to analyze protein expression of the STING pathway. Additionally, the protective effect of Ta-IIA, As-IV and Co via inhibiting STING was further confirmed in models of knockdown STING by siRNA and adding STING agonist.

RESULTS

Both in vitro and in vivo data demonstrated that, compared to Ta-IIA or As-IV alone, the Co exhibited superior efficacy in reducing the area of myocardial infarction, lowering myocardial enzyme levels, and promoting the recovery of myocardial contractility. Furthermore, the Co showed more potent anti-apoptosis, antioxidant, and anti-inflammation effects. Additionally, the Co enhanced the inhibitory effects of Ta-IIA and As-IV on STING phosphorylation and the activation of STING signaling pathway. However, the administration of a STING agonist attenuated the protective effects of the Co, Ta-IIA, and As-IV by compromising their anti-apoptotic, antioxidant, and anti-inflammatory effects in MIRI.

CONCLUSION

Compared to the individual administration of Ta-IIA or As-IV, the combined treatment demonstrated more potent ability in inhibiting apoptosis, oxidative stress, inflammation, and the STING signaling pathway in the context of MIRI, indicating a more powerful protective effect against MIRI.

Calpain inhibition decreases oxidative stress via mitochondrial regulation in a swine model of chronic myocardial ischemia

INTRODUCTION

Calpain overexpression is implicated in mitochondrial damage leading to tissue oxidative stress and myocardial ischemic injury. The aim of this study was to determine the effects of calpain inhibition (CI) on mitochondrial impairment and oxidative stress in a swine model of chronic myocardial ischemia and metabolic syndrome.

METHODS

Yorkshire swine were fed a high-fat diet for 4 weeks to induce metabolic syndrome then underwent placement of an ameroid constrictor to the left circumflex artery. Three weeks later, animals received: no drug (control, "CON"; n= 7); a low-dose calpain inhibitor (0.12 mg/kg; "LCI", n= 7); or high-dose calpain inhibitor (0.25 mg/kg; "HCI", n=7). Treatment continued for 5 weeks, followed by tissue harvest. Cardiac tissue was assayed for protein carbonyl content, as well as antioxidant and mitochondrial protein expression. Reactive oxygen species (ROS) and mitochondrial respiration was measured in H9c2 cells following exposure to normoxia or hypoxia (1%) for 24 h with or without CI.

RESULTS

In ischemic myocardial tissue, CI was associated with decreased total oxidative stress compared to control. CI was also associated with increased expression of mitochondrial proteins superoxide dismutase 1, SDHA, and pyruvate dehydrogenase compared to control. 100 nM of calpain inhibitor decreased ROS levels and respiration in both normoxic and hypoxic H9c2 cardiomyoblasts.

CONCLUSIONS

In the setting of metabolic syndrome, CI improves oxidative stress in chronically ischemic myocardial tissue. Decreased oxidative stress may be via modulation of mitochondrial proteins involved in free radical scavenging and production.

Astragaloside IV protects LO2 cells from oxidative damage caused by radiation-induced bystander effect through Akt/Nrf2 pathway

Background

The protective effects of astragaloside IV (ASIV) on various diseases are well known, but its potential impact on radiation-induced bystander effect (RIBE) has remained unclear.

Objective

This study aimed to explore the protective mechanism of ASIV against oxidative damage caused by RIBE in LO2 cells.

Methods

To construct the RIBE model, the conditioned medium from HepG2 cells irradiated with radiation was transferred to nonirradiated LO2 cells. LY294002, a commonly used phosphatidylinositol 3-kinase/Akt pathway inhibitor, was added to LO2 cells 1 h before exposing HepG2 cells to radiation. LO2 cells were then collected for analyses after RIBE exposure.

Results

The study found that ASIV significantly improved cell proliferation and promoted the recovery of mitochondrial membrane potential while reducing the rate of apoptosis. Western blot analyses demonstrated that ASIV upregulated B-cell lymphoma 2 and downregulated B-cell lymphoma 2-related X protein and cleaved-caspase 3. Measurement of reactive oxygen species, superoxide dismutase, glutathione peroxidase, and malondialdehyde levels showed that ASIV effectively restored the oxidative stress state induced by RIBE. Additionally, immunofluorescence and western blots analyses confirmed that ASIV enhanced the translocation of Nrf2 to the nucleus and activated downstream nicotinamide adenine dinucleotide phosphate: quinine oxidoreductase 1 and heme oxygenase 1. Importantly, Akt pathway inhibitor repressed ASIV-induced activation of Nrf2 and its protective effect against RIBE.

Conclusion

This study demonstrates that ASIV protects LO2 cells against oxidative damage caused by RIBE through activation of the Akt/Nrf2 pathway.

Review on the protective mechanism of astragaloside IV against cardiovascular diseases

Cardiovascular disease is a global health problem. Astragaloside IV (AS-IV) is a saponin compound extracted from the roots of the Chinese herb Astragalus. Over the past few decades, AS-IV has been shown to possess various pharmacological properties. It can protect the myocardium through antioxidative stress, anti-inflammatory effects, regulation of calcium homeostasis, improvement of myocardial energy metabolism, anti-apoptosis, anti-cardiomyocyte hypertrophy, anti-myocardial fibrosis, regulation of myocardial autophagy, and improvement of myocardial microcirculation. AS-IV exerts protective effects on blood vessels. For example, it can protect vascular endothelial cells through antioxidative stress and anti-inflammatory pathways, relax blood vessels, stabilize atherosclerotic plaques, and inhibit the proliferation and migration of vascular smooth muscle cells. Thus, the bioavailability of AS-IV is low. Toxicology indicates that AS-IV is safe, but should be used cautiously in pregnant women. In this paper, we review the mechanisms of AS-IV prevention and treatment of cardiovascular diseases in recent years to provide a reference for future research and drug development.

PINK1/Parkin pathway-mediated mitophagy by AS-IV to explore the molecular mechanism of muscle cell damage

BACKGROUND

Functional disorders of mitochondria are closely related to muscle diseases. Many studies have also shown that oxidative stress can stimulate the production of a large number of reactive oxygen species (ROS), which have various adverse effects on mitochondria and can damage muscle cells.

PURPOSE

In this study, based on our previous research, we focused on the PINK1/Parkin pathway to explore the mechanism by which AS-IV alleviates muscle injury by inhibiting excessive mitophagy.

METHODS

L6 myoblasts were treated with AS-IV after stimulation with hydrogen peroxide (H₂O₂) and carbonyl cyanide m-chlorophenylhydrazone (CCCP). Then, we detected the related indices of oxidative stress and mitophagy by different methods. A PINK1 knockdown cell line was established by lentiviral infection to obtain further evidence that AS-IV reduces mitochondrial damage through PINK1/Parkin.

RESULTS

After mitochondrial damage, the expression of malondialdehyde (MDA) and intracellular ROS in L6 myoblasts significantly increased, while the expression of superoxide dismutase (SOD) and ATP decreased. The mRNA and protein expression levels of Tom20 and Tim23 were decreased, while those of VDAC1 were increased. PINK1, Parkin, and LC3 II mRNA and protein expression increased, and P62 mRNA and protein expression decreased·H₂O₂ combined with CCCP strongly activated the mitophagy pathway and impaired mitochondrial function. However, abnormal expression of these factors could be reversed after treatment with AS-IV, and excessive mitochondrial autophagy could also be reversed, thus restoring the regulatory function of mitochondria. However, AS-IV-adjusted function was resisted after PINK1 knockdown.

CONCLUSION

AS-IV is a potential drug for myasthenia gravis (MG), and its treatment mechanism is related to mediating mitophagy and restoring mitochondrial function through the PINK1/Parkin pathway.

Astragaloside IV Alleviates Brain Injury Induced by Hypoxia via the Calpain-1 Signaling Pathway

Long-term hypoxia can induce oxidative stress and apoptosis in hippocampal neurons that can lead to brain injury diseases. Astragaloside IV (AS-IV) is widely used in the antiapoptotic therapy of brain injury diseases. However, its mechanism of action is still not fully understood. In this study, we investigated the effect of AS-IV on hypoxia-induced oxidative stress and apoptosis in hippocampal neurons and explored its possible mechanism. In vivo, mice were placed in a hypoxic circulatory device containing 10% O₂ and gavaged with AS-IV (60 and 120 mg/kg/d) for 4 weeks. In vitro, mouse hippocampal neuronal cells (HT22) were treated with hypoxia (1% O₂) for 24 hours in the presence or absence of AS-IV, MDL-28170 (calpain-1 inhibitor), or YC-1 (HIF-1α inhibitor). The protective effect of AS-IV on brain injury was further explored by examining calpain-1 knockout mice. The results showed that hypoxia induced damage to hippocampal neurons, impaired spatial learning and memory abilities, and increased oxidative stress and apoptosis. Treatment with AS-IV or calpain-1 knockout improved the damage to hippocampal neurons and spatial learning and memory, attenuated oxidative stress and inhibited cell apoptosis. These changes were verified in HT22 cells. Overexpression of calpain-1 abolished the improvement of AS-IV on apoptosis and oxidative stress. In addition, the effects of AS-IV were accompanied by decreased calpain-1 and HIF-1α expression, and YC-1 showed a similar effect as AS-IV on calpain-1 and caspase-3 expression. In conclusion, this study demonstrates that AS-IV can downregulate the calpain-1/HIF-1α/caspase-3 pathway and inhibit oxidative stress and apoptosis of hippocampal neurons induced by hypoxia, which provides new ideas for studying the antiapoptotic activity of AS-IV.

Biological active ingredients of Astragali Radix and its mechanisms in treating cardiovascular and cerebrovascular diseases

BACKGROUND

With the rising age of the global population, the incidence rate of cardiovascular and cerebrovascular diseases (CCVDs) is increasing, which causes serious public health burden. The efforts for new therapeutic approaches are still being sought since the treatment effects of existing therapies are not quite satisfactory. Chinese traditional medicine proved to be very efficient in the treatment of CCVDs. Well described and established in Chinese medicine, Astragali Radix, has been commonly administered in the prophylaxis and cure of CCVDs for thousands of years.

PURPOSE

This review summarized the action mode and mechanisms of Astragali Radix phytochemicals on CCVDs, hoping to provide valuable information for the future application, development and improvement of Astragali Radix as well as CCVDs treatment.

METHODS

A plenty of literature on biological active ingredients of Astragali Radix used for CCVDs treatment were retrieved from online electronic PubMed and Web of Science databases.

RESULTS

This review highlighted the effects of five main active components in Astragali Radix including astragaloside Ⅳ, cycloastragenol, astragalus polysaccharide, calycosin-7-O-β-d-glucoside, and calycosin on CCVDs. The mechanisms mainly involved anti-oxidative damage, anti-inflammatory, and antiapoptotic through signaling pathways such as PI3K/Akt, Nrf2/HO-1, and TLR4/NF-κB pathway. In addition, the majority active constituents in AR have no obvious toxic side effects.

CONCLUSION

The main active components of Astragali Radix, especially AS-IV, have been extensively summarized. It has been proved that Astragali Radix has obvious therapeutic effects on various CCVDs, including myocardial and cerebral ischemia, hypertension, atherosclerosis, cardiac hypertrophy, chronic heart failure. CAG possesses anti-ischemia activity without toxicity, indicating a worthy of further development. However, high-quality clinical and pharmacokinetic studies are required to validate the current studies.

Inhibition of miRNA-1-Mediated Inflammation and Autophagy by Astragaloside IV Improves Lipopolysaccharide-Induced Cardiac Dysfunction in Rats

Introduction

Astragaloside IV (AS-IV) is one of the main active components isolated from the traditional Chinese medicinal herb, Astragalus membranaceus. The present study was designed to investigate whether the regulation of microRNA-1 (miR-1)-mediated inflammation and autophagy contributes to the protective effect of AS-IV against cardiac dysfunction in rats treated with lipopolysaccharides (LPS).

Methods

Animal model of cardiac dysfunction in rats or cellular model of injured H9c2 heart cell line was established by using LPS. Echocardiography, electron microscopy, enzyme-linked immunosorbent assay, immunofluorescence, quantitative RT-PCR, and Western blotting were used to determine the cardiac function and expression of inflammation- and autophagy-related proteins at both the mRNA and protein levels.

Results

LPS caused cardiac dysfunction in rats or injury in H9c2 cells and induced inflammation and autophagy. Compared with LPS treatment, AS-IV treatment attenuated cardiac dysfunction or cell injury, accompanied by inhibition of inflammation and autophagy. However, the miR-1 mimics partly abolished the effects of AS-IV. In addition, the effect of the miR-1 inhibitor was similar to that of AS-IV in the LPS model. Further analyses showed that AS-IV treatment decreased the mRNA expression of miR-1 in the heart tissue of rats and H9c2 cells treated with LPS.

Conclusion

These results suggest that AS-IV attenuated cardiac dysfunction caused by LPS by inhibiting miR-1-mediated inflammation and autophagy, thereby providing a novel mechanism for the protection against cardiac diseases.

Astragaloside IV Improves the Barrier Damage in Diabetic Glomerular Endothelial Cells Stimulated by High Glucose and High Insulin

Objective. To investigate the protective effect and mechanism of astragaloside IV (AS-IV) on damage in human glomerular endothelial cells (GEnCs) stimulated by high glucose and high insulin. Methods. The transwell method was used to detect the integrity of the cell barrier after AS-IV intervention in a high glucose and high insulin environment for 24 h; immunofluorescence and Western blot methods were used to detect the tight junction protein ZO-1 and claudin-5 expression; intracellular and extracellular 1β (IL-1β) and tumor necrosis factor α (TNFα) were determined by ELISA; expression and activation of AKT, p-AKT, GSK3α/β, and p-GSK3α/β were evaluated by Western blot. Results. The results showed that AS-IV had a significant protective effect on the cell barrier of GEnCs. High glucose or insulin inhibited cell viability in a concentration-dependent manner. High glucose or insulin significantly inhibited glucose uptake and promoted release of reactive oxygen species in GEnCs. Administration with AS-IV dramatically preserved viability of the cells; moreover, the expression of intracellular tight junction proteins was upregulated, inflammatory cytokines including IL-1β and TNFα were decreased, and the AKT-GSK3 pathway participated in modulation of AS-IV in GEnCs cells. Conclusion. We found in the present study that AS-IV can preserve filtration barrier integrity in glomerular endothelial cells under diabetic settings, its effects on increasing the cell energy metabolism and cell viability, inhibiting inflammation and oxidative stress damage, and enhancing tight junction between cells play a role in it; and the intracellular signaling pathway AKT-GSK modulated the above function. Our present finding supplied a new understanding towards development of DN and provided an alternative method on ameliorating DN.

Astragaloside IV-targeting miRNA-1 attenuates lipopolysaccharide-induced cardiac dysfunction in rats through inhibition of apoptosis and autophagy

Astragaloside IV (AS-IV), the major active constituent purified from Astragalus membranaceus, was previously reported to have protective effects against cardiac dysfunction. However, the underlying mechanism remains unknown. In the present study, we investigated the protective effect of AS-IV on lipopolysaccharide (LPS)-induced cardiac dysfunction and explored the potential mechanism by focusing on miRNA-1 (miR-1) at the animal and cellular levels. A series of methods were used, including echocardiography, flow cytometry, ELISA, immunofluorescence, transmission electron microscopy, RT-PCR, and western blotting. The results showed that both AS-IV and the miR-1 inhibitor improved cardiac dysfunction, reduced heart injury, inhibited apoptosis and autophagy, and regulated the expression of calcium- and mitochondrial energy metabolism-related proteins in the heart tissue of rats treated with LPS. Importantly, AS-IV downregulated the expression of miR-1 mRNA in heart tissue. All effects of AS-IV were at least partly abolished by miR-1 mimics. In the in vitro study, both AS-IV and the miR-1 inhibitor inhibited apoptosis and autophagy and regulated the expression of calcium- and mitochondrial energy metabolism-related proteins in heart cells treated with LPS. Similarly, AS-IV downregulated the expression of miR-1 mRNA in heart cells. All effects of AS-IV on cells were at least partly abolished by miR-1 mimics. Furthermore, miR-1 mimics exhibited effects similar to LPS both in animal and cellular studies. Taken together, these results suggest that AS-IV protects against LPS-induced cardiac dysfunction by inhibiting calcium-mediated apoptosis and autophagy by targeting miR-1, highlighting a new mechanism for the therapeutic effect of AS-IV on cardiac dysfunction.

Knockout of calpain-1 protects against high-fat diet-induced liver dysfunction in mouse through inhibiting oxidative stress and inflammation

The present study was designed to investigate the significance of calpain-1 in the high-fat diet (HFD)-induced liver dysfunction and to explore the possible mechanism. C57 mice and calpain-1 knockout (KO) mice were fed with standard diet (SD) or HFD, respectively, for 16 weeks. The activities of calpain, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and superoxide dismutase (SOD) in serum and/or liver of mouse were measured. Lipid profiles in the serum and liver were examined. Contents of oxidized low-density lipoprotein (oxLDL), malondialdehyde (MDA), tumor necrosis factor (TNF-α), and interleukin-6 (IL-6) in serum or/and liver were detected. The results showed that compared with C57 mice fed with SD, HFD-fed C57 mice showed the increased activities of AST and ALT in the serum, which was decreased in calpain-1 KO mice fed with HFD. In addition, knockout of calpain-1 decreased the contents of oxLDL, MDA, TNF-α, and IL-6, while increased SOD activity, in serum and/or liver. However, knockout of calpain-1 had no effects on lipid profiles in both serum and liver. When fed with SD, all these parameters of C57 and calpain-1 KO mice were comparable except for decreased calpain activity in the liver of calpain-1 KO mice. The results suggested that knockout of calpain-1 protects against HFD-induced liver dysfunction through inhibiting oxidative stress and inflammation.

Natural Drugs as a Treatment Strategy for Cardiovascular Disease through the Regulation of Oxidative Stress

Oxidative stress (OS) refers to the physiological imbalance between oxidative and antioxidative processes leading to increased oxidation, which then results in the inflammatory infiltration of neutrophils, increased protease secretion, and the production of a large number of oxidative intermediates. Oxidative stress is considered an important factor in the pathogenesis of cardiovascular disease (CVD). At present, active components of Chinese herbal medicines (CHMs) have been widely used for the treatment of CVD, including coronary heart disease and hypertension. Since the discovery of artemisinin for the treatment of malaria by Nobel laureate Youyou Tu, the therapeutic effects of active components of CHM on various diseases have been widely investigated by the medical community. It has been found that various active CHM components can regulate oxidative stress and the circulatory system, including ginsenoside, astragaloside, and resveratrol. This paper reviews advances in the use of active CHM components that modulate oxidative stress, suggesting potential drugs for the treatment of various CVDs.

Astragaloside IV: An Effective Drug for the Treatment of Cardiovascular Diseases

Cardiovascular disease (CVD), the number one cause of death worldwide, has always been the focus of clinical and scientific research. Due to the high number of deaths each year, it is essential to find alternative therapies that are safe and effective with minimal side effects. Traditional Chinese medicine (TCM) has a long history of significant impact on the treatment of CVDs. The mode of action of natural active ingredients of drugs and the development of new drugs are currently hot topics in research on TCM. Astragalus membranaceus is a commonly used Chinese medicinal herb. Previous studies have shown that Astragalus membranaceus has anti-tumor properties and can regulate metabolism, enhance immunity, and strengthen the heart. Astragaloside IV (AS-IV) is the active ingredient of Astragalus membranaceus, which has a prominent role in cardiovascular diseases. AS-IV can protect against ischemic and hypoxic myocardial cell injury, inhibit myocardial hypertrophy and myocardial fibrosis, enhance myocardial contractility, improve diastolic dysfunction, alleviate vascular endothelial dysfunction, and promote angiogenesis. It can also regulate blood glucose and blood lipid levels and reduce the risk of cardiovascular diseases. In this paper, the mechanism of AS-IV intervention in cardiovascular diseases in recent years is reviewed in order to provide a reference for future research and new drug development.

Taurine attenuates isoproterenol-induced H9c2 cardiomyocytes hypertrophy by improving antioxidative ability and inhibiting calpain-1-mediated apoptosis

Pathological cardiac hypertrophy is ultimately accompanied by cardiomyocyte apoptosis. Apoptosis mainly related to calpain-1-mediated apoptotic pathways. Studies had proved that taurine can maintain heart health through antioxidation and antiapoptotic functions, but the effect of taurine on cardiac hypertrophy is still unclear. This study aimed to determine whether taurine could inhibit calpain-1-mediated mitochondria-dependent apoptotic pathways in isoproterenol (ISO)-induced hypertrophic cardiomyocytes. We found that taurine could inhibit the increase in cell surface area and reduce the protein expression levels of the hypertrophic markers atrial natriuretic peptide, brain natriuretic polypeptide, and β-myosin heavy chain. Taurine also reduced ROS, intracellular Ca²⁺ overload and mitochondrial membrane potential. Moreover, taurine inhibited cardiomyocyte apoptosis by decreasing the protein expression of calpain-1, Bax, t-Bid, cytosolic cytochrome c, Apaf-1, cleaved caspase-9 and cleaved caspase-3 and by enhancing calpastatin and Bcl-2 protein expression. Calpain-1 small interfering RNA transfection results showed similar antiapoptotic effects as the taurine prevention group. However, compared with the two treatments, taurine inhibited the expression of cleaved caspase-9 more significantly. Therefore, we believe that taurine prevents ISO-induced H9c2 cardiomyocyte hypertrophy by inhibiting oxidative stress, intracellular Ca²⁺ overload, the calpain-1-mediated mitochondria-dependent apoptotic pathway and cleaved caspase-9 levels.

Taurine prevents cardiomyocyte apoptosis by inhibiting the calpain-1/cytochrome c pathway during RVH in broilers

The calpain-1-activated apoptotic pathway plays a key role in right ventricular hypertrophy (RVH). Taurine has been shown to attenuate apoptosis by inhibiting calpain activity. This experiment aimed to determine whether taurine could prevent RVH by inhibiting the calpain-1/cytochrome c apoptotic pathway. The broilers were given 1% taurine dissolved in drinking water and were raised at 10 °C ~ 12 °C from day 21 to day 42. At 21 d, 28 d, 35 d and 42 d, the right ventricular (RV) tissues were collected. Increased RVH index, angiotensin II, norepinephrine and atrial natriuretic peptide mRNA expression were reduced by taurine in the broiler RVs. Taurine obviously inhibited cardiomyocyte apoptosis via maintaining the mitochondrial membrane potential and decreased the activation of caspase-9 and caspase-3 in the broiler RVs. The antioxidant assay demonstrated that taurine enhanced the activities of superoxide dismutase, total antioxidant capacity and glutathione peroxidase and the glutathione/glutathione disulfide ratio. Western blot results revealed that taurine also downregulated the expression of calpain-1 and cytosolic cytochrome c while upregulating the expression of Bcl-2/Bax and mitochondrial cytochrome c in broiler cardiomyocytes during RVH. In summary, we found that taurine could enhance cardiomyocyte antioxidant ability and further prevented cardiomyocyte apoptosis by inhibiting the calpain-1/cytochrome c pathway during RVH in broilers.

Astragaloside IV alleviates myocardial damage induced by type 2 diabetes via improving energy metabolism

The aim of the present study was to evaluate the protective effect and mechanism of Astragaloside IV (ASIV) on myocardial injury induced by type 2 diabetes, with a focus on energy metabolism. Blood glucose, the hemodynamic index, left ventricular weight/heart weight (LVW/HW), the left ventricular systolic pressure (LVSP), the left ventricular end diastolic pressure (LVEDP) and cell survival rate were measured in streptozotocin‑induced diabetes model rats. Western blot analysis, PCR, hematoxylin‑eosin and TUNEL staining, flow cytometry and ELISA were used to detect: i) Cardiomyocyte damage indicators such as atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), cytochrome c (Cyt C), caspase‑3, cleaved caspase‑3 and the apoptotic rate; ii) energy metabolism indicators such as ATP/AMP and ADP/AMP; and iii) energy metabolism associated pathway proteins such as peroxisome proliferator‑activated receptor γ coactivator 1‑α (PGC‑1α) and nuclear respiratory factor 1 (NRF1). The present demonstrated increased blood glucose, LVW/HW, LVSP, LVEDP and the cardiomyocyte damage indicators (ANP, BNP, Cyt C and caspase‑3), in the diabetic and high glucose‑treated groups, which were decreased by ASIV. The expression of NRF‑1 and PGC‑1α significantly changed in the model group and was markedly improved following ASIV treatment. Furthermore, the abnormal energy metabolism in the model group was reversed by ASIV. According to the results, ASIV can regulate energy metabolism by regulating the release of PGC‑1α and NRF1 to rescue the abnormal energy metabolism caused by diabetes mellitus, thus decreasing the myocardial damage caused by diabetic cardiomyopathy.

Astragaloside IV regulates NF-κB-mediated cellular senescence and apoptosis of hepatic stellate cells to suppress PDGF-BB-induced activation

Activated hepatic stellate cells (HSCs) are the principal effectors during hepatic fibrosis, which is characterized by the accumulation of extracellular matrix. Therefore, present therapies and investigations into hepatic fibrosis mainly focus on the suppression of activated HSCs. Astragaloside IV (ASIV) is an effective constituent extracted from the plant Astragalus membranaceus and has exhibited anti-fibrotic properties in hepatic fibrosis. However, its protective mechanism against hepatic fibrosis is not fully understood. The present study aimed to investigate the mechanistic role of ASIV on rat HSC-T6 cells activated with platelet-derived growth factor (PDGF)-BB. HSC-T6 cells were activated using PDGF-BB and subsequently treated with ASIV (final concentrations of 20 and 40 µg/ml) for 48 h. ASIV treatment decreased the expression of α1 type I collagen, α-smooth muscle actin and fibronectin on mRNA and protein levels, suggesting that ASIV suppresses PDGF-BB-induced HSC-T6 activation. Senescence-associated β-galactosidase activity, p21, high-mobility group AT-hook 1 and p53, common biomarkers of senescence, were upregulated by ASIV treatment. In addition, the expression of telomerase reverse transcriptase was reduced. ASIV promoted apoptosis of PDGF-BB-activated HSC-T6 cells. The NF-κB signaling pathway, which controls cellular senescence and apoptosis, was demonstrated to be stimulated by ASIV by increasing p65, p52, p50 and inhibitor of NF-κB kinase α expression levels, and by suppressing the expression of NF-κB inhibitor α. Taken together, these results demonstrated that ASIV promoted cellular senescence and apoptosis by activating the NF-κB pathway to suppress PDGF-BB-induced HSC-T6 activation; with potential implications for the treatment of hepatic fibrosis.

Astragaloside IV Alleviates the Myocardial Damage Induced by Lipopolysaccharide via the Toll-Like Receptor 4 (TLR4)/Nuclear Factor kappa B (NF-κB)/Proliferator-Activated Receptor α (PPARα) Signaling Pathway

BACKGROUND We previously reported that astragaloside IV (As-IV) can alleviate myocardial damage induced by lipopolysaccharide (LPS). However, the anti-inflammatory effects of As-IV following LPS stimulation in mice and H9C2 cardiomyocytes remain unclear. The present study was designed to explore the mechanism of action of As-IV. MATERIAL AND METHODS In vivo, C57BL/6J mice were randomly divided into 5 groups: the control group, the LPS group (10 mg/kg), and 3 LPS groups receiving different doses of As-IV (20, 40, and 80 mg/kg). The protective effect of As-IV on LPS-stimulated H9C2 cardiomyocytes was evaluated in vitro. Cardiac function was detected by echocardiography, and H&E staining was used to evaluate morphologic changes. Cardiomyocyte viability was detected by MTT assay. ELISA was used to detect free fatty acid (FFA), interleukin-6 (IL-6), interleukin-1ß (IL-1ß), and tumor necrosis factor alpha (TNF-alpha) levels in mouse serum and in cell supernatant. Adenosine triphosphate (ATP) and adenosine monophosphate (AMP) contents in myocardial tissues and cells were detected by high-performance liquid chromatography. ATP5D and TLR4/NF-kappaB/PPARalpha signaling pathway proteins (TLR4, NF-kappaB, p65, and PPARalpha) were detected by Western blotting. RESULTS As-IV significantly improved cardiac function, myocardial cell viability, and pathological changes and reduced FFA, IL-1ß, IL-6, and TNF-alpha levels. The ATP/AMP ratio in the cardiac tissues of mice and in H9C2 cardiomyocytes was increased compared to that in the LPS group. In addition, As-IV enhanced ATP synthase and PPARalpha protein expression. In H9C2 cardiomyocytes, the p65-specific inhibitor BAY11-7082 exerted similar effects as As-IV. CONCLUSIONS As-IV alleviates LPS-induced myocardial damage by modulating TLR4/NF-kappaB/PPARalpha signaling-mediated energy biosynthesis.

Astragaloside IV reduces cardiomyocyte apoptosis in a murine model of coxsackievirus B3-induced viral myocarditis

Apoptosis plays a crucial role in regulating cardiomyopathy and injuries of coxsackievirus B3 (CVB3)-induced viral myocarditis (VM). It has been reported that Astragaloside IV (AST-IV) from Astragalus membranaceus could inhibit apoptosis under a variety of pathological conditions in vivo or in vitro. However, the functional roles of AST-IV in CVB3-induced VM still remain unknown. Here, we found that AST-IV significantly enhanced survival for CVB3-induced mice. AST-IV protected the mice against CVB3-induced virus myocarditis characterized by the increased body weight, decreased serum level of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH), supressed expression of Ifn-γ, Il-6 in heart, enhanced systolic and diastolic function of left ventricle. At the pathological level, AST-IV ameliorated the mice against CVB3-induced myocardial damage and myocardial fibrosis. In vitro, the results from flow cytometry showed that AST-IV significantly suppressed CVB3-induced cardiomyocytes apoptosis, which also were verified in vivo. Moreover, an increased expression of pro-apoptotic genes including FAS, FASL, cleaved caspase-8 and cleaved caspase-3 was found in CVB3-induced cardiomyocytes, while those was inhibited in cardiomyocytes treated with AST-IV. Taken together, the data suggest that AST-IV protected against CVB3-induced myocardial damage and fibrosis, which may partly attribute to supress activation of FAS/FASL signaling pathway.

Astragaloside IV alleviates doxorubicin induced cardiomyopathy by inhibiting NADPH oxidase derived oxidative stress

Doxorubicin (DOX) is a classic anti-tumor chemotherapeutic used to treat a wide range of tumors. One major downfall of DOX treatment is it can induce fatal cardiotoxicity. Astragaloside IV (AS-IV) is one of the primary active ingredients that can be isolated from the traditional Chinese herbal medicine, Astragalus membranaceus. This study uses both in vitro and in vivo tools to investigate whether AS-IV alleviates DOX induced cardiomyopathy. We found that AS-IV supplementation alleviates body weight loss, myocardial injury, apoptosis of cardiomyocytes, cardiac fibrosis and cardiac dysfunction in DOX-treated mice. Also, DOX-induced cardiomyocyte injury and apoptosis were effectively improved by AS-IV treatment in vitro. NADPH oxidase (NOX) plays an important role in the progress of the oxidative signal transduction and DOX-induced cardiomyopathy. In this study, we found that AS-IV treatment relieves DOX-induced NOX2 and NOX4 expression and oxidative stress in cardiomyocytes. In conclusion, AS-IV, an antioxidant, attenuates DOX-induced cardiomyopathy through the suppression of NOX2 and NOX4.

Astragaloside IV Exerts a Myocardial Protective Effect against Cardiac Hypertrophy in Rats, Partially via Activating the Nrf2/HO-1 Signaling Pathway

Previous evidence suggested that astragaloside IV (ASIV) had a cardioprotective effect, but the potential mechanisms were undetermined. This study is aimed at validating the prevention of cardiac hypertrophy in chronic heart failure (CHF) rats and hypertrophy in H9c2 cardiomyocytes by ASIV and at exploring the potential mechanism involved. CHF rat models of abdominal aortic constriction (AAC) were used with the aim of determining the protective effect of ASIV in cardiac hypertrophy in the rats. We proved that ASIV could attenuate cardiac hypertrophy by improving left ventricular function and structure and showed that the expression of nuclear factor-erythroid 2-related factor 2 (Nrf2) and its downstream gene heme oxygenase-1 (HO-1) increased in the high-dose ASIV intervention group. To further investigate the specific mechanism of ASIV, we hypothesized that ASIV might prevent cardiac hypertrophy via activating the Nrf2/HO-1 signaling pathway. We established a cardiomyocyte hypertrophy model induced by angiotensin II (Ang II), which was then transfected with Nrf2 shRNA, to knock down the expression of the Nrf2 gene. We found that the protective effect of ASIV against Ang II-induced cardiomyocyte hypertrophy was abolished in the Nrf2 shRNA transfection group, ultimately aggravating cardiomyocyte hypertrophy induced by Ang II, and it is possible that oxidative stress may be involved in this process. Our results demonstrated that ASIV improved cardiac function and inhibited cardiac hypertrophy by upregulating Nrf2, and this effect was partially achieved by stimulating the Nrf2/HO-1 signaling pathway, suggesting that ASIV could have therapeutic potential for the treatment of cardiac hypertrophy and CHF.

Lycium barbarum polysaccharide attenuates cardiac hypertrophy, inhibits calpain-1 expression and inhibits NF-κB activation in streptozotocin-induced diabetic rats

Cardiac hypertrophy is one of the key structural changes that occurs in diabetic cardiomyopathy. Previous studies have indicated that the activation of NF-κB by calpain-1, a Ca²⁺-dependent cysteine protease, serves an important role in cardiac hypertrophy. The aim of the present study was to assess the effect of 30 and 60 mg/kg Lycium barbarum polysaccharide (LBP) treatment, the major active ingredient extracted from Lycium barbarum, on cardiac hypertrophy in streptozotocin (STZ) induced diabetic rats. In addition, the present study examined the possible underlying mechanisms of this effect by assessing calpain-1 expression and the NF-κB pathway. The mRNA expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) was determined by reverse transcription-quantitative PCR. Western blotting was used to detect the protein expressions of calpain-1, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1) and toll-like receptor-4 (TLR-4) in the heart tissue. The results revealed that compared with non-diabetic rats, diabetic rats exhibited cardiac hypertrophy. Cardiac hypertrophy was defined by the following: Dysfunction of the cardiac hemodynamics, an increase in the ratios of left ventricular weight/body weight and heart weight/body weight and the increased expressions of ANP and BNP, which serve as hypertrophic markers in cardiac tissue. However, all of these changes were attenuated in diabetic rats treated with LBP. In addition, the protein expression of calpain-1 was increased in the heart tissue of diabetic rats compared with that of non-diabetic rats, where it was inhibited by LBP. LBP also decreased the protein expression of certain inflammatory mediators, IL-6, TNF-α, ICAM-1, VCAM-1 and TLR-4 in diabetic heart tissue. Furthermore, LBP treatment reduced the production of reactive oxygen species, upregulated the protein expression of endothelial nitric oxide synthase and downregulated the protein expression of inducible nitric-oxide synthase. Additionally, LBP increased the protein expression of p65, the subunit of NF-κB and inhibitory protein кB-α in the cytoplasm and reduced p65 expression in the nucleus. In conclusion, LBP improves cardiac hypertrophy, inhibits the expression of calpain-1 and inhibits the activation of NF-κB in diabetic rats.

Simvastatin Improves Cardiac Hypertrophy in Diabetic Rats by Attenuation of Oxidative Stress and Inflammation Induced by Calpain-1-Mediated Activation of Nuclear Factor-κB (NF-κB)

BACKGROUND Simvastatin, an HMG-CoA reductase inhibitor, has been reported to exert multiple protective effects on the cardiovascular system. However, the molecular mechanism remains to be examined. The present study was designed to study the effects of simvastatin on cardiac hypertrophy in diabetic rats and to explore its potential mechanism. MATERIAL AND METHODS Sprague-Dawley rats were assigned into a control (Con) group, a streptozotocin (STZ) group, and a STZ+simvastatin (STZ+SIM) group. The level of reactive oxygen species (ROS) was measured by using dihydroethidium (DHE) staining. The protein expressions of p65, IκBα, vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), calpain-1, and endothelial nitric oxide synthase (eNOS) were examined by Western blot analysis. qPCR was used to detect the levels of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP). RESULTS Simvastatin improved the cardiac hypertrophy of diabetic rats, as demonstrated by decreases in the ratios of left ventricular weight/body weight (LVW/BW) and heart weight/body weight (HW/BW) and by the downregulation of mRNA expression of BNP and ANP in the heart tissue. Simvastatin decreased the protein expressions of VCAM-1, ICAM-1, IL-6, and TNF-α, increased eNOS protein expression, and limited an increase in ROS levels in the heart tissue. Simvastatin increased IkBa protein expression in cytoplasm and inhibited the translocation of p65, the subunit of nuclear factor-κB (NF-κB) to the nucleus from the cytoplasm of the heart tissue. Furthermore, simvastatin attenuated the activity of calpain and calpain-1 protein expression in heart tissue. CONCLUSIONS Simvastatin attenuates cardiac hypertrophy in diabetic rats, which might be due to the attenuation of oxidative stress and inflammation induced by calpain-1-mediated activation of NF-κB.

Calcium Sensing Receptor-Related Pathway Contributes to Cardiac Injury and the Mechanism of Astragaloside IV on Cardioprotection

Activation of calcium sensing receptor (CaSR) contributes to cardiac injury, but the underlying mechanism has not yet been examined. Astragaloside IV (AsIV) was previously reported to exhibit protective effects against various myocardial injuries. The aim of the present study was to investigate the underlying mechanism of CaSR in cardiac hypertrophy and apoptosis and to evaluate whether the protective effect of AsIV against myocardial injury is associated with CaSR and its related signaling pathway. In vivo and in vitro myocardial injury was induced by isoproterenol (Iso) or GdCl₃ (a CaSR agonist) in rats and heart H9C2 cells. Cardiac cell hypertrophy, apoptosis, function, Mitochondrial Membrane Potential (MMP), mitochondrial ultrastructure, and [Ca²⁺]_i, as well as the protein expression of CaSR, calcium/calmodulin-dependent protein kinase II (CaMKII), calcineurin (CaN), sarcoplasmic reticulum Ca²⁺-ATPase2a (SERCA2a), and the inositol 1,4,5-trisphosphate receptor (IP3R), were measured in vivo and/or in vitro. The results showed that AsIV attenuated cardiac hypertrophy and apoptosis and attenuated impairments in cardiac function, mitochondrial structure, and MMP induced by Iso or GdCl₃ in rat myocardial tissue and H9C2 cells. Importantly, AsIV treatment inhibited the enhancement of [Ca²⁺]_i and CaSR expression induced by Iso or GdCl₃, an effect similar to that of the CaSR antagonist NPS2143. In addition, AsIV treatment repressed CaSR, CaMKII, and CaN activation and inhibited NFAT-3 nuclear translocation. Mechanistic analysis using lentivirus infection showed that CaSR overexpression activated the CaMKII and CaN signaling pathways and that this response was enhanced by Iso. The results suggested that CaSR-mediated changes in [Ca²⁺]_i and CaMKII and CaN signaling pathways contribute to cardiac hypertrophy and apoptosis and are involved in the protective effect of astragaloside IV against cardiac injury.

Blockage of endoplasmic reticulum stress attenuates nilotinib-induced cardiotoxicity by inhibition of the Akt-GSK3β-Nox4 signaling

Cardiotoxicity is a critical side-effect of nilotinib during treatment for cancer, such as chronic myeloid leukemia, while the potential signaling mechanisms remain unclear. The role of and the relationship between endoplasmic reticulum (ER) stress and mitochondrial dysfunction was investigated in nilotinib-induced cardiac H9C2 injury as a suitable cell model. Our results showed that ER stress was persistently induced in nilotinib-treated cells, evidenced by increase of GRP78, CHOP, ATF4 and XBP1 as well as phospho-PERK^Thr980. The results from 4-phenylbutyrate (PBA, an ER stress inhibitor) and SC79 (a specific Akt activator) suggested that ER stress increased activity of glycogen synthase kinase-3 beta (GSK3β) that is reflected by decrease of phospho-GSK3β^Ser9, through downregulation of phospho-Akt^Ser473, and that prolonged ER stress and activated GSK3β involved nilotinib-induced apoptosis. In addition, the data from JNK inhibition using SP600125 showed that over-activated JNK was responsible for Akt de-phosphorylation. Moreover, the abundance of NADPH oxidase (Nox4) was significantly increased following nilotinib treatment, which was prevented by SB216763 (a specific GSK3β inhibitor). Additionally, mitochondrial dysfunction was indicated by reduced mitochondrial membrane potential (MMP) level and increased reactive oxygen species level. In nilotinib-treated cells, knockdown of Nox4 preserved MMP level, abrogated reactive oxygen species production, and decreased apoptosis. Accordingly, our data demonstrated that inhibition of ER stress may protect cardiomyocytes against nilotinib toxicity potentially through inactivation of Akt-GSK3β-Nox4 signaling. These findings may provide an attractive therapeutic target for treatment of nilotinib-related cardiotoxicity.

Inhibition of cardiotrophin‑1 overexpression is involved in the anti‑fibrotic effect of Astrogaloside IV

Astragaloside IV (AsIV), one of the major active ingredients in Astragalus membranaceus, has demonstrated remarkable antifibrotic effects via its antioxidative activity. Cardiac fibrosis is an important pathological mechanism during cardiac remodelling associated with heart failure. In the present study, the mechanism underlying the antifibrotic effect of AsIV upon isoprenaline (ISO) stimulation was investigated. AsIV significantly improved cardiac fibrosis in vivo and dose‑dependently inhibited ISO‑induced CF proliferation in vitro. The ISO‑triggered elevation in reactive oxygen species (ROS) levels was remarkably inhibited by AsIV, as well as ROS scavenger N‑acetylcysteine (NAC), and not affected by cardiotrophin‑1 (CT‑1) knockdown. In addition, AsIV effectively reversed ISO‑induced upregulation of CT‑1 expression, which was blunted by pretreatment with NAC. Cardiac fibroblast (CF) proliferation and collagen Ι overexpression induced by ISO stimulation were effectively abrogated by AsIV, NAC, and CT‑1 small interfering RNA transfection. Taken together, these results demonstrated that AsIV was able to effectively inhibit ISO‑induced CF proliferation and collagen production through negative regulation of ROS‑mediated CT‑1 upregulation.

Diabetes and Cardioplegia

Cardiac surgery with cardiopulmonary bypass and cardioplegic arrest is associated with injury to the vasculature and microcirculation leading to coronary microvascular dysfunction, permeability changes and cardiac dysfunction. In the setting of cardiopulmonary bypass with cardioplegia, poorly-controlled diabetes is associated with significant changes in endothelium-dependent and independent vascular dysfunction, vascular reactivity, vascular permeability, protein expression, cell death, coronary/peripheral microcirculation and reduced vasomotor tone leading to hypotension and impaired endothelial function. The gene expression profiles after cardiopulmonary bypass with cardioplegic arrest is quantitatively and qualitatively different in patients with diabetes. Gene expression profiling capitalizing on the differences between patients with and without diabetes is a good place to identify potential medical targets.

Compatibility of Tanshinone IIA and Astragaloside IV in attenuating hypoxia-induced cardiomyocytes injury

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal medicines including Tanshinone IIA (TanIIA) and Astragaloside IV (AsIV) are widely used in Asia as therapeutic agents for cardiovascular diseases, due to their complementary roles and shared properties based on the theory of traditional Chinese medicine and pharmacological researches. However, the underlying pathological mechanisms for their efficacy are still unclear. In addition, the compatibility or incompatibility of the herbal medicines when administered with other herbal remedies or with prescription drugs is unknown.

AIM OF THE STUDY

We aimed to investigate the compatibility of TanIIA and AsIV in protecting cardiomyocytes against hypoxia-induced injury.

MATERIALS AND METHODS

Cultured cardiomyocytes were stimulated in hypoxia condition, in the absence or presence of the two herbal compounds, TanIIA and AsIV. Indicators were determined by cytotoxicity assay, quantitative PCR, ELISA, flow cytometry assay, immunofluorescence staining and western blot.

RESULTS

Either TanIIA alone or the combined herbal compounds inhibited hypoxia-triggered chemokines production including CCL2/5/19, CXCL2 and Transwell assay-indicated monocyte/macrophage recruitment, cytokines production including TNF-α and IL-6. While AsIV alone or the combined herbal compounds attenuated hypoxia-induced cell apoptosis indicated by decreased Annexin V⁺ cells and the ratio of Bax/Bcl-2, but no significant effect of the herbal compounds was observed in modulating cell apoptosis following both hypoxia and TNF-α stimulation. As an anti-apoptotic factor, stress granule formation was further enhanced by AsIV alone or the combined herbal compounds in hypoxia or heat shock stress. Moreover, immunoblotting analysis indicated that stress-responsive mitogen-activated protein kinases (MAPK) pathways including the phosphorylation of ERK1/2, p38 and JNK were inhibited while the phosphorylation of Akt in phosphatidylinositol 3-kinase (PI3K) -Akt pathway for cell survival was restored by the herbal compounds. Among these results, the combination of TanIIA and AsIV comprised most of the beneficial properties tested, although their combination did not improve the maximal effects achieved by any of the compounds alone.

CONCLUSIONS

Taken together, these data suggest a compatibility of TanIIA and AsIV in protecting cardiomyocyte against hypoxia-induced injury.

Astragaloside IV inhibits isoprenaline‑induced cardiac fibrosis by targeting the reactive oxygen species/mitogen‑activated protein kinase signaling axis

Cardiac fibrosis is considered an important pathological mechanism in the progression of cardiac remodeling and heart failure. Astragaloside IV (AsIV) is a major active ingredient in Astragalus membranaceus. In a preliminary experiment, it was demonstrated that this naturally occurring substance exhibited cardioprotective effects via preventing cardiomyocyte hypertrophy and apoptosis. The present study aimed to investigate the effects of AsIV on β‑adrenergic receptor (β‑AR)‑mediated cardiac fibrosis, and the associated mechanism. Cell Counting Kit‑8 (CCK‑8) assay was used to examine the proliferation of rat cardiac fibroblast (CF) cultures. Collagen I secretion was detected by ELISA. Dihydroethidium was used to determine intracellular ROS levels. Western blotting was used to examine the expression level of total and phosphorylated mitogen‑activated protein kinases (MAPKs). In the present study, the effects of AsIV on β‑adrenergic receptor (β‑AR) ‑mediated cardiac fibrosis were investigated, and the associated mechanism was revealed. Isoprenaline (ISO) is a selective β‑AR agonist, and treatment with AsIV significantly inhibited (ISO)‑triggered cardiac fibroblast proliferation and type I collagen synthesis. In addition, ISO resulted in a significant elevation of reactive oxygen species (ROS) levels and phosphorylation of the three profibrotic MAPKs, namely extracellular signal‑regulated kinase, p38MAPK and c‑Jun N‑terminal kinase. AsIV effectively reversed the aforementioned ISO‑induced alterations. In addition, N‑acetylcysteine, a typical ROS scavenger, mimicked the inhibitory effects of AsIV on MAPK activation. The present study demonstrated that AsIV may inhibit ISO‑induced cardiac fibrosis by suppressing ROS‑mediated MAPK activation.

Astragaloside IV protects rat gastric mucosa against aspirin-induced damage

Aspirin (Asp) is commonly used as an anti-inflammatory drug, but the long-term usage of Asp can lead to severe gastrointestinal damage. Thus the co-administering of Asp with another drug that can suppress its side effect while having no impact on its anti-inflammatory activity would be ideal. Astragaloside IV (AST-IV) is a natural anti-inflammatory compound that has been shown to protect rat gastric mucosa from anhydrous ethanol-inflicted damage. In this study, we investigated whether AST-IV could protect rat gastric mucosa against Asp-induced gastric mucosal damage. Wistar rats administered 150mg/kg Asp showed significant damage to the gastric mucosa, as revealed by gastric damage score and histological evaluation. However, this was largely abolished by co-administering Asp and 25mg/kg or 50mg/kg AST-IV. The protective mechanism of AST-IV involved the suppression of Asp-induced inhibition of cycloxygenase-1 (COX-1) expression, prostaglandin E₂ (PGE₂) production, superoxide dismutase (SOD) activity and nitric oxide (NO) production. AST-IV blocked Asp-induced inhibition of SOD activity through preventing Asp from inhibiting the expression of SOD-1, both at the mRNA and protein levels. AST-IV did not appear to interfere with the anti-inflammatory activity of Asp since COX-2 level in model gastritis rats treated with Asp plus AST-IV was equally suppressed as in model gastritis rats treated with Asp alone. The results clearly showed that AST-IV could neutralize the toxicity of Asp while having no impact on its anti-inflammatory activity. AST-IV could therefore be considered as a potential drug for relieving the side effect associated with the long-term usage of Asp.

Pretreatment with Astragaloside IV protects human umbilical vein endothelial cells from hydrogen peroxide induced oxidative stress and cell dysfunction via inhibiting eNOS uncoupling and NADPH oxidase - ROS - NF-κB pathway

Endothelial cell injury caused by reactive oxygen species (ROS) plays a critical role in the pathogenesis of cardiovascular disorders. Astragaloside IV (AsIV) possesses potent antioxidant properties against oxidative stress through undefined mechanism(s). We sought to investigate whether AsIV protects human umbilical vein endothelial cells (HUVECs) from hydrogen peroxide (H₂O₂) induced oxidative stress focusing on eNOS uncoupling and the NADPH oxidase - ROS - NF-κB pathway. Compared with HUVECs incubated with H₂O₂ alone, pretreatment with AsIV significantly increased the viability of HUVECs, which was accompanied with apparent increase in nitric oxide (NO) production and decrease in intracellular superoxide anion production. Furthermore, pretreatment with AsIV increased endothelial nitric oxide synthase (eNOS) dimer/monomer ratio and its critical cofactor tetrahydrobiopterin (BH₄) content, decreased Nox4 protein expression (the most abundant Nox isoform in HUVECs), inhibited translocation of NF-κB p65 subunit into nuclear fraction while enhanced the protein expression of IκB-α (the inhibitor of NF-κB p65), reduced the levels of IL-1β, IL-6, and TNF-α in HUVECs medium, and decreased iNOS protein expression. These results suggest that AsIV may protect HUVECs from H₂O₂-induced oxidative stress via inhibiting NADPH oxidase - ROS - NF-κB pathway and eNOS uncoupling.