Cardioprotective effect of the xanthones from Gentianella acuta against myocardial ischemia/reperfusion injury in isolated rat heart

7'-Hydroxyl substituted xanthones from Gentianella acuta revert hepatic steatosis in obese diabetic mice through preserving mitochondrial homeostasis

Mitochondrial dysfunction is a key contributor to the development and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Xanthones, bioactive flavonoids derived from various herbal medicines, are renowned for their anti-inflammatory, antioxidant, and anti-tumor properties. This study aimed to investigate the effects of xanthones isolated from Gentianella acuta on hepatic steatosis and the underlying mechanisms regulating mitochondrial function. We report that a xanthone fraction (400 mg/kg/day) effectively prevented obesity and hepatic steatosis in obese diabetic db/db mice in vivo. In vitro, xanthones inhibited lipid accumulation and mitochondrial dysfunction induced by high glucose (20 mM) and high palmitic acid (200 µM) in HepG2 cells. Mechanistically, norathyriol (NTR), a major in vivo metabolite of Gentianella acuta, inhibited the activity of dynamin-related protein 1 (Drp1), a protein associated with mitochondrial fission, and prevented its translocation from the cytoplasm to the mitochondria by inhibiting the orphan nuclear receptor (Nur77). Additionally, NTR increased the expression of the mitochondrial outer membrane protein FUN14 domain containing 1 (FUNDC1), which stimulated mitophagy to clear damaged or dysfunctional mitochondria under overnutrition conditions. We also discovered that reactive oxygen species (ROS) targeted FUNDC1, leading to mitochondrial damage, but this effect could be reversed by 7'-hydroxyl substituted xanthones. Collectively, 7'-hydroxyl substituted xanthones inhibited mitochondrial fission while promoting mitophagy, ultimately improving mitochondrial and liver function in diabetic hepatic steatosis. The modulation of mitochondrial function by 7'-hydroxyl substituted xanthones presents a novel approach for treating hepatic steatosis, particularly in diabetic conditions.

Xanthones explore the mechanism of p53/p21 signaling pathway to prevent cardiac aging and epigenetic regulation of Nrf2 gene

Gentianella acuta (GA) is a folk medicine used by Ewenki people in Inner Mongolia to treat heart disease. Transcriptional inhibition caused by the increase of DNMT1/3A/3B levels inhibited Nrf2, an anti-aging factor with antioxidant effect in aging myocardia, and the level of Nrf2 decreased with the increase of age. The main chemical component of GA, xanthones, can reverse this inhibition. In this study, D-gal was injected subcutaneously to establish an aging mouse model, and echocardiography was helpful to evaluate myocardial damage. Myocardial histological changes were detected by haematoxylin eosin and Masson's trichrome staining. The activities of catalase (CAT) and total superoxide dismutase (T-SOD) and the content of malondialdehyde (MDA) in serum of mice were detected to investigate the relationship between GA and oxidative stress. The serum levels of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were determined to investigate the effects of GA on aging mice. Results showed that Xanthones could alleviate myocardial damage and fibrosis, significantly improve diastolic dysfunction, gradually decrease MDA content, gradually increase T-SOD and CAT activities, and decrease serum TNF-α, IL-6 and IL-1β contents in aging mice. Reduce cardiac structural disorders, reduce inflammatory infiltration. In addition, GA reduces inflammation by promoting Nrf2 expression, inhibiting DNMT1/3A/3B levels, and activating the p53/p21 signaling pathway. This study suggests that GA has a protective effect on D-gal-induced cardiac aging, which may be related to the activation of p53/p21 signaling pathway and epigenetic regulation of Nrf2 level.

Hong-Bai-Lan-Shen Extract Alleviates the CoCl2-Induced Apoptosis in H9C2 Cells by Regulating the AMPK Pathway

This study aims to explore the protective effects of Hong-bai-lan-shen (HBLS) extract, a traditional Chinese medicine compound, on myocardial injury based on metabolomics. H9C2 cells were cultured with HBLS extract for 12 h, and then the cells were cultured in a CoCl2-containing medium, a model simulating the ischemic-hypoxic damage in myocardial cells, for an additional 12 h. The cell viability, cytotoxicity, intracellular metabolite and reactive oxygen species (ROS), mitochondrial membrane potential, apoptosis, and adenosine monophosphate-activated protein kinase (AMPK) signal pathway were determined. The results showed that HBLS extract significantly increased cell viability, stabilized cell morphology, reduced lactate dehydrogenase (LDH) release and ROS production, blocked cysteine-aspartic acid protease 3 (caspase-3) and bcl-2-associated X protein (Bax) expression and decreased apoptotic cell numbers. Meanwhile, HBLS increased membrane potential and the expression of B-cell lymphoma-2 (Bcl-2). Additionally, HBLS extract upregulated the expression of AMPK, PI3K, and protein kinase B (AKT) (p < 0.05, p < 0.01). These findings suggest that HBLS extract has a protective effect on myocardial cells by regulating the AMPK signal pathway and may be a promising therapeutic candidate for ischemic heart disease.

Endothelial-Protective Actions of Diethylether Extract from Gentiana kochiana and Xanthone Gentiacaulein Against Oxidized LDL-Induced Injury-In Vitro Evaluation

Endothelial dysfunction is an early pathophysiological event in atherosclerosis. The endothelial-protective abilities of diethylether extract (EE) from the Gentiana kochiana (Gentianaceae) herb and its main component, xanthone aglycone gentiacaulein (GC), were evaluated in an oxidized low-density lipoprotein (oxLDL)-treated EA.hy926 endothelial cell line. The EE and GC actions were assessed using cell viability assays, flow cytometry, immunoblot, DPPH, NBT, TBARS, conjugated diene formation, and Griess tests. Both EE and GC prevented oxLDL-induced apoptosis by reducing intracellular reactive oxygen species levels, mitochondrial depolarization, and caspase activation in EA.hy926 cells. EE and GC dose-dependently diminished oxLDL-induced cellular lipid peroxidation. In cell-free conditions, EE moderately scavenged superoxide anions and had no affinity toward DPPH radicals, GC did not interact with either of investigated free radicals, while both EE and GC effectively delayed Cu²⁺-induced LDL oxidation. EE and GC upregulated oxLDL-suppressed protective Akt/CREB/eNOS and ERK signals and restored oxLDL-reduced nitric oxide levels. Therefore, EE and GC effectively counteract oxLDL-induced endothelial apoptosis by reducing oxidative stress, promoting mitochondrial recovery, and enhancing the prosurvival Akt/CREB/eNOS axis and ERK activity. Our study is the first to demonstrate that xanthone-rich EE from aerial parts of G. kochiana and xanthone GC alleviate oxLDL-induced endothelial cell injury, underscoring their potential for cardiovascular protection.

Effect of Gentianella acuta (Michx.) Hulten against the arsenic-induced development hindrance of mouse oocytes

The current study was designed to investigate the alleviative effect of Gentianella acuta (Michx.) Hulten (G. acuta) against the sodium arsenite (NaAsO2)-induced development hindrance of mouse oocytes. For this purpose, the in vitro maturation (IVM) of mouse cumulus-oocyte complexes (COCs) was conducted in the presence of NaAsO2 and G. acuta, followed by the assessments of IVM efficiency including oocyte maturation, spindle organization, chromosome alignment, cytoskeleton assembly, cortical granule (CGs) dynamics, redox regulation, epigenetic modification, DNA damage, and apoptosis. Subsequently, the alleviative effect of G. acuta intervention on the fertilization impairments of NaAsO2-exposed oocytes was confirmed by the assessment of in vitro fertilization (IVF). The results showed that the G. acuta intervention effectively ameliorated the decreased maturation potentials and fertilization deficiency of NaAsO2-exposed oocytes but also significantly inhibited the DNA damages, apoptosis, and altered H3K27me3 expression level in the NaAsO2-exposed oocytes. The effective effects of G. acuta intervention against redox dysregulation including mitochondrial dysfunctions, accumulated reactive oxygen species (ROS) generation, glutathione (GSH) deficiency, and decreased adenosine triphosphate (ATP) further confirmed that the ameliorative effects of G. acuta intervention against the development hindrance of mouse oocytes were positively related to the antioxidant capacity of G. acuta. Evidenced by these abovementioned results, the present study provided fundamental bases for the ameliorative effect of G. acuta intervention against the meiotic defects caused by the NaAsO2 exposure, benefiting the future application potentials of G. acuta intervention in these nutritional and therapeutic research for attenuating the outcomes of arseniasis.

Bellidifolin ameliorates isoprenaline-induced cardiac hypertrophy by the Nox4/ROS signalling pathway through inhibiting BRD4

To date, there is no effective therapy for pathological cardiac hypertrophy, which can ultimately lead to heart failure. Bellidifolin (BEL) is an active xanthone component of Gentianella acuta (G. acuta) with a protective function for the heart. However, the role and mechanism of BEL action in cardiac hypertrophy remain unknown. In this study, the mouse model of cardiac hypertrophy was established by isoprenaline (ISO) induction with or without BEL treatment. The results showed that BEL alleviated cardiac dysfunction and pathological changes induced by ISO in the mice. The expression of cardiac hypertrophy marker genes, including ANP, BNP, and β-MHC, were inhibited by BEL both in mice and in H9C2 cells. Furthermore, BEL repressed the epigenetic regulator bromodomain-containing protein 4 (BRD4) to reduce the ISO-induced acetylation of H3K122 and phosphorylation of RNA Pol II. The Nox4/ROS/ADAM17 signalling pathway was also inhibited by BEL in a BRD4 dependent manner. Thus, BEL alleviated cardiac hypertrophy and cardiac dysfunction via the BRD4/Nox4/ROS axes during ISO-induced cardiac hypertrophy. These findings clarify the function and molecular mechanism of BEL action in the therapeutic intervention of cardiac hypertrophy.

1,3,5,8-Tetrahydroxyxanthone suppressed adipogenesis via activating Hedgehog signaling in 3T3-L1 adipocytes

In this study, we investigated the effect of 1,3,5,8-tetrahydroxyxanthone (THX) on the adipogenesis of 3T3-L1 adipocytes. THX, a xanthone isolated from Gentianella acuta, inhibited lipid accumulation in 3T3-L1 adipocytes and reduced the protein levels of the key adipogenic transcriptional factors, peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), in a dose-dependent manner. In addition, THX enhanced the transcriptional activity of Gli1 known as the key indicator of Hedgehog (Hh) signaling activity and increased the expression of Gli1 and its upstream regulator Smo. The Smo activator SAG exerted the similar effect with THX on regulating Gli1, Smo, PPARγ and C/EBPα expression, which led to the suppression of fat formation in 3T3-L1 adipocytes. Furthermore, we found that the inhibitory effect of THX on adipogenesis was derived from regulation of the early stage of adipogenesis. These results suggest that THX suppresses the differentiation of adipocyte through Hh signaling and may be considered as a potent agent for the prevention of obesity.

Gentianella acuta improves TAC-induced cardiac remodelling by regulating the Notch and PI3K/Akt/FOXO1/3 pathways

Cardiac remodelling mainly manifests as excessive myocardial hypertrophy and fibrosis, which are associated with heart failure. Gentianella acuta (G. acuta) is reportedly effective in cardiac protection; however, the mechanism by which it protects against cardiac remodelling is not fully understood. Here, we discuss the effects and mechanisms of G. acuta in transverse aortic constriction (TAC)-induced cardiac remodelling in rats. Cardiac function was analysed using echocardiography and electrocardiography. Haematoxylin and eosin, Masson's trichrome, and wheat germ agglutinin staining were used to observe pathophysiological changes. Additionally, real-time quantitative reverse transcription polymerase chain reaction and western blotting were used to measure protein levels and mRNA levels of genes related to myocardial hypertrophy and fibrosis. Immunofluorescence double staining was used to investigate the co-expression of endothelial and interstitial markers. Western blotting was used to estimate the expression and phosphorylation levels of the regulatory proteins involved in autophagy and endothelial-mesenchymal transition (EndMT). The results showed that G. acuta alleviated cardiac dysfunction and remodelling. The elevated levels of myocardial hypertrophy and fibrosis markers, induced by TAC, decreased significantly after G. acuta intervention. G. acuta decreased the expression of LC3 II and Beclin1, and increased p62 expression. G. acuta upregulated the expression of CD31 and vascular endothelial-cadherin, and prevented the expression of α-smooth muscle actin and vimentin. Furthermore, G. acuta inhibited the PI3K/Akt/FOXO1/3a pathway and activated the Notch signalling. These findings demonstrated that G. acuta has cardioprotective effects, such as alleviating myocardial fibrosis, inhibiting hypertrophy, reducing autophagy, and blocking EndMT by regulating the PI3K/Akt/FOXO1/3a and Notch signalling pathways.

Bellidifolin Inhibits SRY-Related High Mobility Group-Box Gene 9 to Block TGF-β Signalling Activation to Ameliorate Myocardial Fibrosis

Myocardial fibrosis is the main morphological change of ventricular remodelling caused by cardiovascular diseases, mainly manifested due to the excessive production of collagen proteins. SRY-related high mobility group-box gene 9 (SOX9) is a new target regulating myocardial fibrosis. Bellidifolin (BEL), the active component of G. acuta, can prevent heart damage. However, it is unclear whether BEL can regulate SOX9 to alleviate myocardial fibrosis. The mice were subjected to isoproterenol (ISO) to establish myocardial fibrosis, and human myocardial fibroblasts (HCFs) were activated by TGF-β1 in the present study. The pathological changes of cardiac tissue were observed by HE staining. Masson staining was applied to reveal the collagen deposition in the heart. The measurement for expression of fibrosis-related proteins, SOX9, and TGF-β1 signalling molecules adopted Western blot and immunohistochemistry. The effects of BEL on HCFs, activity were detected by CCK-8. The result showed that BEL did not affect cell viability. And, the data indicated that BEL inhibited the elevations in α-SMA, Collagen I, and Collagen III by decreasing SOX9 expression. Additionally, SOX9 suppression by siRNA downregulated the TGF-β1 expression and prevented Smad3 phosphorylation, as supported by reducing the expression of α-SMA, Collagen I, and Collagen III. In vivo study verified that BEL ameliorated myocardial fibrosis by inhibiting SOX9. Therefore, BEL inhibited SOX9 to block TGF-β1 signalling activation to ameliorate myocardial fibrosis.

Gentianella acuta mitigates cardiovascular damage and inflammation in diet-induced hypercholesterolaemic rats

Gentianella acuta (G. acuta) has been widely used as a traditional medicine by Chinese Mongolian populations for the treatment of heart diseases and has also been tested in modern pharmacological experiments. However, the effects of G. acuta on cardiovascular damage and inflammation under conditions of hypercholesterolaemia remain unclear. The present study investigated the effects and mechanisms of the water extract of G. acuta on cardiovascular damage and inflammation caused by a high-cholesterol diet. Male Sprague-Dawley rats were fed a high-cholesterol diet for 4 weeks to establish the hypercholesterolaemia rat model, and they were administered physiological saline or 1.2 g/kg of G. acuta by gavage starting from the 15th day. After the last administration, the blood, heart and thoracic aorta samples were collected and examined. It was revealed that G. acuta treatment could ameliorate cardiomyocyte disorder and thoracic aortic vessel wall damage, reduce serum lipid levels and inflammatory factors and improve heart function. Compared with the Model group, the serum levels of triglycerides, total cholesterol, low-density lipoprotein and tumour necrosis factor-α were decreased, and the high-density lipoprotein and interleukin-10 levels were increased in the Model-G group. Moreover, in both the heart and thoracic aorta, G. acuta reduced the expression and phosphorylation of inhibitor of nuclear factor kappa-B kinase β (IKKβ), inhibitor of NF-κB-α (IκBα) and p-nuclear factor kappa-B (NF-κB). Therefore, G. acuta may exert an inhibitory effect on the IKK/IκB/NF-κB signalling pathway to protect the heart and thoracic aorta in hypercholesterolaemic rats.

Xanthone Glucosides: Isolation, Bioactivity and Synthesis

Xanthones are secondary metabolites found in plants, fungi, lichens, and bacteria from a variety of families and genera, with the majority found in the Gentianaceae, Polygalaceae, and Clusiaceae. They have a diverse range of bioactivities, including anti-oxidant, anti-bacterial, anti-malarial, anti-tuberculosis, and cytotoxic properties. Xanthone glucosides are a significant branch of xanthones. After glycosylation, xanthones may have improved characteristics (such as solubility and pharmacological activity). Currently, no critical review of xanthone glucosides has been published. A literature survey including reports of naturally occurring xanthone glucosides is included in this review. The isolation, structure, bioactivity, and synthesis of these compounds were all explored in depth.

Tanshinone‑IIA inhibits myocardial infarct via decreasing of the mitochondrial apoptotic signaling pathway in myocardiocytes

Myocardial ischemia triggers an inflammatory reaction and oxidative stress that increases apoptosis of myocardiocytes. It has been evidenced that tanshinone‑IIA (Tan‑IIA) protects against heart failure post‑myocardial infarction via inhibition of the apoptotic pathway. The purpose of the present study was to investigate the therapeutic effect of Tan‑IIA in a rat model of myocardial ischemia, and explore the possible mechanism of Tan‑IIA in myocardiocytes. The rat model of myocardial ischemia was established by left anterior descending coronary artery and rats received treatment with either Tan‑IIA (10 mg/kg) or PBS for 20 days continuously. The cardiac function in the experimental rat model was detected using the Sequoia 512 echocardiography system on day 21. The cell viability of myocardiocytes was assessed by CCK‑8 assay. Apoptosis of myocardiocytes and myocardial tissue was evaluated by TUNEL assay. The infarct size of the myocardial ischemia rat was determined through 2,3,5‑triphenyltetrazolium chloride (TTC) and Evan blue double staining assay. The expression levels of apoptotic factors were assessed by immunohistochemistry, western blotting and immunofluorescence. The results demonstrated that Tan‑IIA reduced myocardial infarct size and improved the myocardial function in myocardial ischemia rats. Compared with PBS, Tan‑IIA treatment decreased myocardial tissue apoptosis and the expression levels of caspase‑3, Cyto c and Apaf‑1 in myocardial tissue. Tan‑IIA increased the viability of impaired myocardiocytes, inhibited apoptosis of impaired myocardiocytes and increased Bcl‑2 and Bak expression in myocardiocytes. In addition, Tan‑IIA increased Bim and CHOP, decreased TBARS, ROS and H2O2 production, decreased ATF4 and IRE1α expression, and reduced intracellular calcium and oxidative stress in myocardiocytes. Furthermore, caspase‑3 overexpression blocked Tan‑IIA‑decreased apoptosis of myocardiocytes. In conclusion, the data in the present study indicated that Tan‑IIA improved myocardial infarct and apoptosis via the endoplasmic reticulum stress‑dependent pathway and mitochondrial apoptotic signaling pathway.

Bellidifolin Ameliorates Isoprenaline-Induced Myocardial Fibrosis by Regulating TGF-β1/Smads and p38 Signaling and Preventing NR4A1 Cytoplasmic Localization

Myocardial fibrosis is closely related to high morbidity and mortality. In Inner Mongolia, Gentianella amarella subsp. acuta (Michx.) J.M.Gillett (G. acuta) is a kind of tea used to prevent cardiovascular diseases. Bellidifolin (BEL) is an active xanthone molecule from G. acuta that protects against myocardial damage. However, the effects and mechanisms of BEL on myocardial fibrosis have not been reported. In vivo, BEL dampened isoprenaline (ISO)-induced cardiac structure disturbance and collagen deposition. In vitro, BEL inhibited transforming growth factor (TGF)-β1-induced cardiac fibroblast (CF) proliferation. In vivo and in vitro, BEL decreased the expression of α-smooth muscle actin (α-SMA), collagen Ⅰ and Ⅲ, and inhibited TGF-β1/Smads signaling. Additionally, BEL impeded p38 activation and NR4A1 (an endogenous inhibitor for pro-fibrogenic activities of TGF-β1) phosphorylation and inactivation in vitro. In CFs, inhibition of p38 by SB203580 inhibited the phosphorylation of NR4A1 and did not limit Smad3 phosphorylation, and blocking TGF-β signaling by LY2157299 and SB203580 could decrease the expression of α-SMA, collagen I and III. Overall, both cell and animal studies provide a potential role for BEL against myocardial fibrosis by inhibiting the proliferation and phenotypic transformation of CFs. These inhibitory effects might be related to regulating TGF-β1/Smads pathway and p38 signaling and preventing NR4A1 cytoplasmic localization.

Protective action of the ginsenoside Rh3 in a rat myocardial ischemia-reperfusion injury model by inhibition of apoptosis induced via p38 mitogen-activated protein kinase/caspase-3 signaling

OBJECTIVE

To investigate the protective effects of the ginsenoside Rh3 on rats subjected to myocardial ischemia-reperfusion (MIR) via its impact on caspase-3 and the p38 mitogen-activated protein kinase (MAPK) pathway.

METHODS

Fifteen male Sprague-Dawley rats were randomly categorized into the MIR group (MY group, n = 5), sham surgery group (SS group, n = 5), and ginsenoside Rh3 group (GR group, n = 5).

RESULTS

The MY group exhibited the largest myocardial infarctions compared with the GR and SS groups. The GR group exhibited significantly higher cell viability of cardiomyocytes and significantly decreased apoptosis compared with the MY group. Fibrils of infarcted tissue in the GR group were disordered but less swollen, with a more organized fibril orientation than those in the MY group. The GR group showed reduced p-p38 MAPK protein and caspase-3 mRNA expression levels compared with the MY and SS groups.

CONCLUSIONS

Rh3 significantly improved myocardial necrosis and caspase-3 levels in myocardial tissues by suppressing the p38 MAPK pathway, thereby inhibiting caspase-3 involvement in apoptosis. Thus, Rh3 was effective in inhibiting the escalated apoptotic pathway in myocardial infarction and can potentially serve as a useful therapeutic agent to rescue myocardial infarction.

RETRACTED: Sevoflurane up-regulates microRNA-204 to ameliorate myocardial ischemia/reperfusion injury in mice by suppressing Cotl1

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the reliability of the Western blot results in Figures 4C+E and 7E, which appear to have a similar phenotype as seen in many other publications, as detailed here: https://pubpeer.com/publications/CE1E814DD630D160BEEBFC2842FE45; and here: https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. The journal requested that the corresponding author comment on these concerns and provide the raw data. The authors did not respond to this request and therefore the Editor-in-Chief decided to retract the article.

Gentianella acuta prevents acute myocardial infarction induced by isoproterenol in rats via inhibition of galectin-3/TLR4/MyD88/NF-кB inflammatory signalling

Gentianella acuta (G. acuta), as a folk medicine, was used to treat heart disease by the Ewenki people in Inner Mongolia. However, the effect of G. acuta on acute myocardial infarction (AMI) is not clear. To explore the mechanisms of G. acuta on isoproterenol (ISO)-induced AMI, rats were administered G. acuta for 28 days, then injected intraperitoneally with ISO (85 mg/kg) on days 29 and 30. An electrocardiogram helped to evaluate the myocardial injury. Serum lactate dehydrogenase (LDH), creatinine kinase (CK) and aspartate aminotransferase (AST) levels were evaluated, and haematoxylin eosin, Masson's trichrome staining and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining were used to detect myocardial histological changes. Radioimmunoassay was used to measure serum tumour necrosis factor alpha (TNFα) and interleukin (IL)-6. An enzyme-linked immunosorbent assay kit was used to analyse serum galectin-3 (Gal-3) levels. Immunohistochemistry, Western blotting and reverse transcription polymerase chain reaction were used to examine relevant molecular events. The results revealed that pre-treatment with G. acuta decreased the elevation in the ST segment; reduced serum LDH, CK and AST levels; alleviated cardiac structure disorder; and reduced inflammatory infiltration, abnormal collagen deposition and cardiomyocyte apoptosis that were induced by ISO. Furthermore, pre-treatment with G. acuta inhibited serum Gal-3 levels and Gal-3 expression in heart tissue, and also impeded TLR4/MyD88/NF-кB signalling activation, which ultimately prevented the expression of inflammatory cytokines. The study indicated that pre-treatment with G. acuta protects against ISO-induced AMI, and the protective role may be related to inhibiting Gal-3/TLR4/MyD88/NF-кB inflammatory signalling.

Cardioprotective effect of isorhamnetin against myocardial ischemia reperfusion (I/R) injury in isolated rat heart through attenuation of apoptosis

In this study, we investigated the effects of isorhamnetin on myocardial ischaemia reperfusion (I/R) injury in Langendorff‐perfused rat hearts. Isorhamnetin treatment (5, 10 and 20 μg/mL) significantly alleviated cardiac morphological injury, reduced myocardial infarct size, decreased the levels of marker enzymes (LDH and CK) and improved the haemodynamic parameters, reflected by the elevated levels of the left ventricular developed pressure (LVDP), coronary flow (CF) and the maximum up/down velocity of left ventricular pressure (+dp/dt_max). Moreover, isorhamnetin reperfusion inhibited apoptosis of cardiomyocytes in the rats subjected to cardiac I/R in a dose‐dependent manner concomitant with decreased protein expression of Bax and cleaved‐caspase‐3, as well as increased protein expression of Bcl‐2. In addition, I/R‐induced oxidative stress was manifestly mitigated by isorhamnetin treatment, as showed by the decreased malondialdehyde (MDA) level and increased antioxidant enzymes activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH‐Px). These results indicated that isorhamnetin exerts a protective effect against I/R‐induced myocardial injury through the attenuation of apoptosis and oxidative stress.

The aqueous extract of Gentianella acuta improves isoproterenol‑induced myocardial fibrosis via inhibition of the TGF‑β1/Smads signaling pathway

Gentianella acuta (G. acuta) is one of the most commonly used herbs in Chinese Mongolian medicine for the treatment of heart disease. Previously, it was found that G. acuta ameliorated cardiac function and inhibited isoproterenol (ISO)-induced myocardial fibrosis in rats. In this study, the underlying anti-fibrotic mechanism of G. acuta was further elucidated. Histopathological changes in the heart were observed by hematoxylineosin, Masson trichrome and wheat germ agglutinin staining. Relevant molecular events were investigated using immunohistochemistry and western blotting. The results revealed that G. acuta caused improvements in myocardial injury and fibrosis. G. acuta also inhibited collagens I and III and α-smooth muscle actin production in heart tissue. G. acuta downregulated the expression of transforming growth factor β1 (TGF-β1) and notably inhibited the levels of phosphorylation of TGF-β receptors I and II. Furthermore, G. acuta caused downregulation of the intracellular mothers against decapentaplegic homolog (Smads)2 and 4 expression and inhibited Smads2 and 3 phosphorylation. The results further demonstrated that the mechanism underlying anti-myocardial fibrosis effects of G. acuta was based upon the suppression of the TGF-β1/Smads signaling pathway. Therefore, G. acuta may be a potential therapeutic agent for ameliorating myocardial fibrosis.

Proteinase‑activated receptor 2 deficiency is a protective factor against cardiomyocyte apoptosis during myocardial ischemia/reperfusion injury

Previous studies have established that proteinase‑​activated receptor 2 (PAR2) activation protects against myocardial ischemia/reperfusion injury (MI/RI). However, the role of PAR2 deficiency in MI/RI remains unclear. The aim of the present study was to examine the effect of PAR2 deficiency on cardiomyocyte apoptosis and to clarify the potential molecular mechanisms for its protective effect against MI/RI. Using a mouse model of MI/RI, cardiac function was evaluated by echocardiography, infarct size was assessed by triphenyltetrazolium chloride staining, and myocardial cell apoptosis was measured by terminal deoxynucleotide transferase‑mediated dUTP nick end‑labeling staining. Annexin V/propidium iodide staining, and expression of Bcl‑2 and cleaved PARP were determined to assess apoptosis in myocardial H9c2 cells exposed to hypoxia/reoxygenation (H/R) injury‑simulating MI/RI. Phosphorylated ERK1/2, JNK, and p38 MAPK protein expression levels were analyzed by western blotting. The findings indicated that PAR2 deficiency markedly reduced cardiomyocyte apoptosis in the MI/RI mouse model, as well as in myocardial H9c2 cells exposed to H/R. Furthermore, PAR2 knockdown clearly prevented phosphorylation of ERK1/2 and JNK in myocardial H9c2 cells. The results revealed that PAR2 deficiency alleviated MI/RI‑associated apoptosis by inhibiting phosphorylation of ERK1/2 and JNK. Therefore, targeted PAR2 silencing may be a potential therapeutic approach for alleviation of MI/RI.

Protective effect of T3 peptide, an active fragment of tumstatin, against ischemia/reperfusion injury in rat heart

Ischemia/reperfusion (I/R)-induced oxidative stress is a serious clinical problem in the reperfusion therapy for ischemic diseases. Tumstatin is an endogenous bioactive peptide cleaved from type IV collagen α3 chain. We previously reported that T3 peptide, an active subfragment of tumstatin, exerts cytoprotective effects on H₂O₂-induced apoptosis through the inhibition of intracellular reactive oxygen species (ROS) production in H9c2 cardiomyoblasts. In this study, we investigated whether T3 peptide has cardioprotective effects against I/R injury by using in vitro and ex vivo experimental models. H9c2 cardiomyoblasts were stimulated with oxygen and glucose deprivation (OGD) for 12 h followed by reoxygenation for 1-8 h (OGD/R; in vitro model). The cells were treated with T3 peptide (30-1000 ng/ml) during OGD. Ten minutes after the pre-perfusion of T3 peptide (300 ng/ml), Langendorff perfused rat hearts were exposed to ischemia for 30 min followed by reperfusion for 1 h (ex vivo model). T3 peptide inhibited OGD/R-induced apoptosis through the inhibition of mitochondrial ROS production and dysfunction in H9c2 cardiomyoblasts. T3 peptide also prevented I/R-induced cardiac dysfunction, arrhythmia and myocardial infarction in the perfused rat heart. In conclusion, we for the first time demonstrated that T3 peptide exerts cardioprotective effects against I/R injury.

An integrated characterization of contractile, electrophysiological, and structural cardiotoxicity of Sophora tonkinensis Gapnep. in human pluripotent stem cell-derived cardiomyocytes

BACKGROUND

Cardiotoxicity remains an important concern in drug discovery and clinical medication. Meanwhile, Sophora tonkinensis Gapnep. (S. tonkinensis) held great value in the clinical application of traditional Chinese medicine, but cardiotoxic effects were reported, with matrine, oxymatrine, cytisine, and sophocarpine being the primary toxic components.

METHODS

In this study, impedance and extracellular field potential (EFP) of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were recorded using the cardio non-labeled cell function analysis and culture system (Cardio-NLCS). The effects of matrine, oxymatrine, cytisine, and sophocarpine (2, 10, 50 μM) on cell viability; level of lactate dehydrogenase (LDH), creatine kinase MB isoenzyme (CK-MB), and cardiac troponin I (CTn-I); antioxidant activities; production of reactive oxygen species (ROS) and malondialdehyde (MDA); and disruption of intracellular calcium homeostasis were also added into the integrated assessment.

RESULTS

The results showed that matrine and sophocarpine dose-dependently affected both impedance and EFP, while oxymatrine and cytisine altered impedance significantly. Our study also indicated that cardiotoxicity of matrine, oxymatrine, cytisine, and sophocarpine was related to the disruption of calcium homeostasis and oxidative stress. Four alkaloids of S. tonkinensis showed significant cardiotoxicity with dose dependence and structural cardiotoxicity synchronized with functional changes of cardiomyocytes.

CONCLUSIONS

This finding may provide guidance for clinical meditation management. Furthermore, this study introduced an efficient and reliable approach, which offers alternative options for evaluating the cardiotoxicity of the listed drugs and novel drug candidates.

Protective role of Gentianella acuta on isoprenaline induced myocardial fibrosis in rats via inhibition of NF-κB pathway

Gentianella acuta (Michx.) Hulten (G. acuta) has been widely used in Mongolian medicines for the treatment of cardiovascular diseases in Ewenki and Oroqen, Inner Mongolia autonomous region, China. The aim of this study was to investigate the effects and related mechanism of G. acuta on isoproterenol (ISO)-induced oxidative stress, fibrosis, and myocardial damage in rats. Male Sprague Dawley rats were randomly divided into the normal control group, ISO induced group and ISO+G. acuta treatment group. Rats were administered with ISO subcutaneously (5 mg/kg/day) for 7 days, and were orally administered simultaneously with aqueous extracts of G. acuta for 21 days. This investigation showed G. acuta treatment ameliorated cardiac structural disorder, excessive collagenous fiber accumulation and cardiac malfunction. Compared with the ISO induced model group, G. acuta treatment increased superoxide dismutase (SOD) activities and glutathione (GSH) level, prevented the rise of malondialdehyde (MDA), and decreased hydroxyproline contents in the heart tissues. Moreover, G. acuta reduced the expression of transforming growth factor β1 (TGF-β1) and connective tissue growth factor (CTGF), and inhibited the expression and activation of NF-κB-P65 in myocardial tissues. These results suggested that G. acuta protects against ISO-induced cardiac malfunction probably by preventing oxidative stress, and fibrosis, and the mechanism might be through inhibiting NF-κB pathway.

Xanthones isolated from Gentianella acuta and their protective effects against H2O2-induced myocardial cell injury

In the present study, two new xanthones, (5'S,8'S)-1,3,5,8-tetrahydroxyxanthone(7→2')-1,3,5,8-tetrahydroxy-5',6',7',8'-tetrahydroxanthone (1), 5-hydroxy-3,4,6-trimethoxyxanthone-1-O-β-D-glucopyranoside (2), and eight known xanthones (3-10) were isolated from the whole plants of Gentianella acuta. Their structures were identified by the spectroscopic analyses (HR-ESI-MS, and 1D and 2D NMR). Meanwhile, cell-protective effects against H₂O₂-induced H9c2 cardiomyocyte injury and cytotoxic activities of compounds 1-10 were also determined.

Bioactive Constituents from the Whole Plants of Gentianella acuta (Michx.) Hulten

As a Mongolian native medicine and Ewenki folk medicinal plant, Gentianella acuta has been widely used for the treatment of diarrhea, hepatitis, arrhythmia, and coronary heart disease. In the course of investigating efficacy compounds to treat diarrhea using a mouse isolated intestine tissue model, we found 70% EtOH extract of G. acuta whole plants had an inhibitory effect on intestine contraction tension. Here, nineteen constituents, including five new compounds, named as gentiiridosides A (1), B (2), gentilignanoside A (3), (1R)-2,2,3-trimethyl-4-hydroxymethylcyclopent-3-ene-1-methyl-O-β-d-glucopyranoside (4), and (3Z)-3-hexene-1,5-diol 1-O-α-l-arabinopyranosyl(1→6)-β-d-glucopyranoside (5) were obtained from it. The structures of them were elucidated by chemical and spectroscopic methods. Furthermore, the inhibitory effects on motility of mouse isolated intestine tissue of the above mentioned compounds and other thirteen iridoid- and secoiridoid-type monoterpenes (7-10, 13-16, 18, 19, 21, 22, and 25) previously obtained in the plant were analyzed. As results, new compound 5, some secoiridoid-type monoterpenes 7, 10, 12-14, 16, and 17, as well as 7-O-9'-type lignans 31 and 32 displayed significant inhibitory effect on contraction tension at 40 μM.