Myocardial Ischemia-reperfusion In Rats Research Articles

Cardioprotective effects of the aqueous extract of Echinops cephalotes on myocardial ischemia-reperfusion in rats by modulation of MMP-2, MMP-9, TIMP, and oxidative stress

Echinops plants have received great attention for the treatment of many diseases due to pharmacological properties such as their antidiabetic, antioxidant, and anti-inflammatory characteristics. The major purpose of the present study was to investigate the cardioprotective benefits of Echinops cephalotes (Ech) against myocardial ischemia-reperfusion (MI/R) injury. Male Wistar rats were randomly allocated to three groups: sham, MI, and MI + Ech. The left coronary artery (LAD) was blocked for 30 minutes to induce MI. In the treatment group, rats were given 150 mg/kg/day of Ech extract for 28 days. Aqueous extracts were made from Echinops plants. To study heart function, fibrosis, cardiac damage indicators, and oxidative stress factors, echocardiography, Masson's trichrome staining, and biochemical tests were used. The expression of matrix metalloproteinase 2 and 9 (MMP2 and MMP-9) and tissue inhibitor of metalloproteinase (TIMP) was determined using Western blotting. Tissue damage was assessed using hematoxylin and eosin staining. MI group exhibited significantly reduced ejection fraction (EF) and fractional shortening (FS), enhanced levels of lactate dehydrogenase (LDH), creatine kinase MB (CK-MB), cardiac Troponin I (cTnI), and malondialdehyde (MDA), as well as a decrease in the Glutathione (GSH) tissue content, reduced activity of superoxide dismutase (SOD), increasing fibrosis, upregulations of MMP-2 and MMP-9, and reduction of TIMP compared to the sham group. The findings suggest that Ech in particular, could be a promising therapeutic agent to reduce the damage in MI by targeting oxidative stress and modulating the activities of matrix metalloproteinases and their tissue inhibitors.

Cardioprotective effect of Cinnamamide derivative compound 10 against myocardial ischemia-reperfusion through regulating cardiac autophagy via Sirt1

Background and purposeOur previous research discovered that cinnamamide derivatives are a new type of potential cardioprotective agents myocardial ischemia-reperfusion (MIR) injury, among which Compound 10 exhibits wonderful beneficial action in vitro. However, the exact mechanism of Compound 10 still needs to be elucidated. Experimental approachThe protective effect of Compound 10 was determined by detecting the cell viability and LDH leakage rate in H9c2 cells subjected to H2O2. Alterations of electrocardiogram, echocardiography, cardiac infarct area, histopathology and serum myocardial zymogram were tested in MIR rats. Additionally, the potential mechanism of Compound 10 was explored through PCR. Network pharmacology and Western blotting was conducted to monitor levels of proteins related to autophagic flux and mTOR, autophagy regulatory substrate, induced by Compound 10 both in vitro and in vivo, as well as expressions of Sirtuins family members. Key resultsCompound 10 significantly ameliorated myocardial injury, as demonstrated by increased cell viability, decreased LDH leakage in vitro, and declined serum myocardial zymogram, ST elevation, cardiac infarct area and improved cardiac function and microstructure of heart tissue in vivo. Importantly, Compound 10 markedly enhanced the obstruction of autophagic flux and inhibited excessive autophagy initiation against MIR by decreased ATG5, Rab7 and increased P-mTOR and LAMP2. Furthermore, Sirt1 knockdown hindered Compound 10’s regulation on mTOR, leading to interrupted cardiac autophagic flux. Conclusions and implicationsCompound 10 exerted cardioprotective effects on MIR by reducing excessive autophagy and improving autophgic flux blockage. Our work would take a novel insight in seeking effective prevention and treatment strategies against MIR injury.

Naltrindole attenuates irreversible Hypercontracture during Myocardial Ischemia by a Novel Mechanism and elicits robust cardioprotective effects in Myocardial Ischemia/Reperfusion Injury

Introduction: Previous studies have shown that naltrindole (NTI) produced robust cardioprotective effects (e.g.~80% reduction of infarct size) in both ex-vivo (2.5-5μM) and in-vivo (3.75-7.5 mg/kg) rat myocardial ischemia-reperfusion (MIR) injury models. We recently showed that NTI 100-200μM attenuated phorbol 12-myristate 13-acetate (PMA) induced polymorphonuclear leukocytes (PMNs) superoxide (SO) release by a novel mechanism of action (MOA) devoid of opioid receptors. We hypothesize NTI’s novel MOA is a reduction of intracellular calcium (Ca2+). To test this hypothesis, we conducted PMN SO release and isolated perfused MIR assays using KB-R7943(KB). KB is known to reduce intracellular Ca2+ via inhibition of reverse mode Na+/Ca2+ exchanger and therefore should attenuate PMN SO release, myocardial ischemic hypercontracture, infarct size, and left ventricular end diastolic pressure (LVEDP). Methods: PMNs and hearts isolated from anesthetized male Sprague Dawley (SD) rats (~400g SO release assay, ~300g for perfused hearts). PMN SO release was stimulated using PMA (100nM) ± NTI 10-200 μM, KB 5-20 μM, or vehicle (0.5% DMSO; controls) and measured spectrophotometrically as a change in absorbance @ 550nm over 390 secs and cell viability was determined using 0.2% Trypan blue exclusion. We then infused NTI 1.25-5μM, KB 10-20μM, or naloxone (NX; negative control) 10μM for 5 min into perfused hearts, just prior to global I (30min)/R(45min). Cardiac LV function was measured via a pressure transducer and infarct size using 1% triphenyltetrazolium chloride staining in MIR assay. Data were analyzed using ANOVA and Fischers post-hoc analysis, with p<0.05 considered statistically significant. Results: PMN SO release assay: KB 10 μM, KB 20 μM, NTI 100 μM (~3.75 mg/kg), and NTI 200 μM(~7.5 mg/kg) significantly attenuated PMA induced PMN SO release by ~40% (KB 10μM, n=7, p<0.05), ~50% ((KB 20μM, n=7, p<0.05), ~30% (NTI 100 μM, n=7, p<0.05), 75% (NTI 200μM, n=7, p<0.05) respectively when compared to untreated control (n=10). MIR assay: NTI 5μM, 2.5μM, 1.25μM and KB 20 μM reduced infarct size (4.8±3%, n=5, p<0.05), (6.8±0.8%, n=6, p<0.05), (12.2±3%, n=5), and (2.9±2%, n=5, p<0.05) respectively compared to vehicle (14.1±2%, n=9) and NX 10μM controls (18±3%, n=3). NTI 5 μM and KB 20 μM had significantly improved LVEDP to (32.4±11%, n=5, p<0.05) and (22.8±4%, n=5, p<0.05) respectively compared to vehicle control (72.4±6%, n=9) and NX 10μM controls(54.2±8%, n=3) Conclusion: NTI and KB showed concentration-dependent effects on reducing PMN SO release. Both NTI (2.5μM, 5μM) and KB (20μM) reduced infarct size and improved LVEDP. The novel MOA of NTI is most likely mediated via a reduction in intracellular Ca2+ and subsequent hypercontracture during myocardial ischemia. The infarct reducing effect of NTI can benefit patients who will undergo elective PCI, CABG, and transplants. Funding: This study was funded by the Philadelphia College of Osteopathic Medicine, Department of Biomedical Sciences, Division of Research, and the Center for Chronic Diseases of Aging and Young Therapeutics, LLC. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Identification of a mechanism promoting mitochondrial sterol accumulation during myocardial ischemia-reperfusion: role of TSPO and STAR.

Hypercholesterolemia is a major risk factor for coronary artery diseases and cardiac ischemic events. Cholesterol per se could also have negative effects on the myocardium, independently from hypercholesterolemia. Previously, we reported that myocardial ischemia-reperfusion induces a deleterious build-up of mitochondrial cholesterol and oxysterols, which is potentiated by hypercholesterolemia and prevented by translocator protein (TSPO) ligands. Here, we studied the mechanism by which sterols accumulate in cardiac mitochondria and promote mitochondrial dysfunction. We performed myocardial ischemia-reperfusion in rats to evaluate mitochondrial function, TSPO, and steroidogenic acute regulatory protein (STAR) levels and the related mitochondrial concentrations of sterols. Rats were treated with the cholesterol synthesis inhibitor pravastatin or the TSPO ligand 4'-chlorodiazepam. We used Tspo deleted rats, which were phenotypically characterized. Inhibition of cholesterol synthesis reduced mitochondrial sterol accumulation and protected mitochondria during myocardial ischemia-reperfusion. We found that cardiac mitochondrial sterol accumulation is the consequence of enhanced influx of cholesterol and not of the inhibition of its mitochondrial metabolism during ischemia-reperfusion. Mitochondrial cholesterol accumulation at reperfusion was related to an increase in mitochondrial STAR but not to changes in TSPO levels. 4'-Chlorodiazepam inhibited this mechanism and prevented mitochondrial sterol accumulation and mitochondrial ischemia-reperfusion injury, underlying the close cooperation between STAR and TSPO. Conversely, Tspo deletion, which did not alter cardiac phenotype, abolished the effects of 4'-chlorodiazepam. This study reveals a novel mitochondrial interaction between TSPO and STAR to promote cholesterol and deleterious sterol mitochondrial accumulation during myocardial ischemia-reperfusion. This interaction regulates mitochondrial homeostasis and plays a key role during mitochondrial injury.

Retracted: miR-451 on Myocardial Ischemia-Reperfusion in Rats by Regulating AMPK Signaling Pathway.

[This retracts the article DOI: 10.1155/2021/9933998.].

Abstract 17814: Naltrindole Mitigates Rigor During Myocardial Ischemia by a Novel Mechanism and Shows Translational Cardioprotection in Myocardial Ischemia-Reperfusion Injury Models

Introduction: Naltrindole (NTI) was cardioprotective in both ex-vivo (5μM) and in-vivo (7.5mg/kg) rat myocardial ischemia-reperfusion (MIR) models. Recently, we showed that NTI 50-200μM (~2-7.5mg/kg, in-vivo) attenuated phorbol ester-induced PMN superoxide release by a novel mechanism devoid of opioid receptors. We hypothesize that NTI exerts its cardioprotective effects (and therefore, its effects on the infarct size) in a dose-dependent manner. Methods: Ex-vivo studies were done with Sprague Dawley male rats using a Langendorff apparatus. Excised hearts were pretreated with Krebs buffer (controls), NTI 1.25μM, NTI 2.5μM, or NTI 5μM for 5 min, followed by 30 min of global ischemia (I) and a 45 min reperfusion (R) period. In-vivo studies were performed with Sprague Dawley female rats which received infusions (NTI 0.2-1.0 mg/kg, 3.75 mg/kg, or 7.5 mg/kg) through the jugular vein (0.4mL/min) over 5 mins before regional I was induced by occluding the LAD artery for 30 min followed by a 3 hr R period. Cardiac function was measured in both studies through a pressure transducer placed into the left ventricle. Results: Ex-vivo: NTI 5μM, 2.5μM and 1.25μM reduced infarct size by 66% (4.8±1%, n=5, p<0.05), 52% (6.8±0.8%, n=6, p<0.05), and 13% (12.2±3%, n=5) respectively compared to control (14.1±1%, n=7). NTI 5μM (1358±300 mmHg) had significantly improved dP/dt max at the end of R compared to untreated controls (576±163, p<0.05). In-vivo: High Dose (7.5 mg/kg x 5 min = 37.5 mg/kg [total dose]), Intermediate Dose (3.75 mg/kg x 5 min = 18.75 mg/kg [total dose]), and Low Dose (0.2-1.0 mg/kg x 5 min = 1.0-5.0 mg/kg [total dose]) NTI reduced infarct size by 81% (11±4%, n=5, p<0.05), 55% (26±7%, n=5, p<0.05), and 4% (55±4%, n=18) respectively compared to untreated controls (57±2%, n=15). DP/dt max was similar among all study groups at the end of R. Conclusions: Both ex-vivo and in-vivo MIR models showed a dose-dependent effect on reducing infarct size. This effect is most likely correlated with a reduction in rigor during myocardial ischemia. Future in-vivo studies will test 2 mg/kg and 7.5 mg/kg in rat and porcine MIR respectively. The infarct reducing effect of NTI might benefit patients who will opt for elective PCI, CABG, and transplant.

Astragaloside IV attenuates cardiac hypertrophy in rats born from mothers with intrauterine hypoxia through the PKCβII/Egr‑1 pathway.

Astragaloside IV (AS-IV) is a naturally occurring agent that confers several wide-ranging reported pharmacological effects, such as cardioprotective, antioxidative and pro-angiogenic activities. Although it was previously reported that AS-IV could attenuate neonatal rat myocardial ischemia-reperfusion injury, the possible effects of AS-IV on the development of cardiac hypertrophy associated with intrauterine hypoxia (IUH) remain unclear. The present study established a model of IHU by placing the pregnant rats in a plexiglass chamber with an oxygen supply of 10% before neonatal rat delivery. To investigate the in vivo effect of AS-IV on cardiac hypertrophy, neonatal rats with hypertension were randomly grouped to receive AS-IV (20 mg/kg), AS-IV (40 mg/kg), AS-IV (80 mg/kg) or vehicle for 12 weeks, followed by left ventricular (LV) hemodynamics and heart tissue histological analysis. Rats born from mothers with IHU displayed pathological features of cardiac hypertrophy. However, AS-IV 40 and 80 mg/kg significantly decreased the heart/body weight (BW), LV mass (LVM)/BW, heart mass/tibia length (TL) and LVM/TL ratios. H&E staining showed that 40 and 80 mg/kg AS-IV prevented the morphometric changes induced by IHU. According to data from LV hemodynamics measurements, AS-IV 80 mg/kg reversed the increased systolic blood pressure, diastolic blood pressure, LV systolic pressure, LV end-diastolic pressure, dP/dt maximum and heart rate induced by IHU. Mechanistically, ERK1/2 activation and early growth response 1 (Egr-1) protein expression were both upregulated by IHU induction, which was reversed by AS-IV treatment. In conclusion, these data suggested that AS-IV could attenuate cardiac hypertrophy in neonatal rats born from mothers with IHU through the protein kinase C β type isoform 2/Egr-1 pathway, but the underlying mechanism requires further investigation.

Nobiletin alleviates myocardial ischemia-reperfusion injury via ferroptosis in rats with type-2 diabetes mellitus

Susceptibility to myocardial ischemia-reperfusion (IR) injury in type-2 diabetes (T2DM) remains disputed, although studies have reported that ferroptosis is associated with myocardial IR injury. Nobiletin, a flavonoid isolated from citrus peels, is an antioxidant that possesses anti-inflammatory and anti-diabetic activities. However, it remains unknown whether nobiletin has any protective effects on susceptibility to myocardial IR injury during T2DM in rats via ferroptosis. To investigate the effects and underlying mechanisms of nobiletin on myocardial IR injury during T2DM, we induced myocardial IR model in rats at T2DM onset vs mature disease. We also established a high-fat high-glucose (HFHG) and hypoxia-reoxygenation (H/R) model in H9c2 cells to imitate abnormal glycolipid metabolism during T2DM. Myocardial injury, oxidative stress and ferroptosis towards myocardial IR in rats with mature T2DM but not at T2DM onset were increased. These changes were restored under treatment with ferrostain-1 or nobiletin. Both ferrostain-1 and nobiletin decreased the expression of ferroptosis-related proteins including Acyl-CoA synthetase long chain family member 4 (ACSL4) and nuclear receptor coactivator 4 (NCOA4) but not glutathione peroxidase 4 (GPX4) in rats with mature T2DM and cells with HFHG and H/R injury. Nobiletin strengthened the effect of si-ACSL4 on inhibiting ACSL4 expression, and also inhibited the effect of Erastin or oe-ACSL4 on increasing ACSL4 expression. Taken together, our data indicates that ferroptosis involves in susceptibility to myocardial IR injury in rats during T2DM. Nobiletin has therapeutic potential for alleviating myocardial IR injury associated with ACSL4- and NCOA4-related ferroptosis.

Cardioprotective efficacy of ultrasound-targeted nitrofatty acid microbubbles in rat myocardial ischemia-reperfusion injury model

Over 1 million Americans suffer from acute myocardial infarction (AMI) annually. Although mortality from AMI has decreased, post-AMI congestive heart failure is increasing due to microvascular obstruction (MVO). MVO comprises mechanical obstruction, along with oxidate stress and inflammation. Currently available treatments for MVO are not consistently effective. Hence, we have been developing ultrasound (US)-targeted microbubble cavitation (UTMC) as a potential treatment for MVO. Nitro-fatty acids (NFA) are pleiotropic signaling molecules with broad anti-inflammatory actions, potentially beneficial for the treatment of MVO. NFA are amphipathic thus can seamlessly integrate into the phospholipid shell of MBs. Thus, we have constructed microbubbles with NFA (NFABs) to treat ischemia-reperfusion injury (IRI) with UTMC in the rat myocardial model. Left anterior descending (LAD) coronary artery was ligated for 30 min, allowing for IRI. After 15 min of reperfusion, UTMC + NFABs therapy was administered. Echocardiography measurements were recorded at baseline, during ligation and post-treatment. Left ventricular fractional shortening (%) was calculated and NFA concentration in cardiac tissue was determined. UTMC with NFABs exhibited promising efficacy in improving fractional shortening post IRI, and in targeted myocardial delivery of NFA. Studies assessing ejection fraction, myocardial area at risk, histopathology, inflammatory burden, oxidative stress and cytoprotective biomarkers are underway.

Effects of Toll-Like Receptor4 Gene Modified Bone Marrow Mesenchymal Stem Cells (BMSCs) Transplantation on Expression of Basic Fibroblast Growth Factor (bFGF) and Follistatin-Like-1 (FSTL1) in Myocardial Ischemia-Reperfusion Rats

This study assesses the effects of TLR4 gene modified BMSCs transplantation on the expression of bFGF and FSTL1 in myocardial ischemia-reperfusion rats. 30 male SD rats were assigned into control group (myocardial ischemia model), BMSCs group (model + BMSCs transplantation) and transfection group (model + TLR4 gene modified BMSCs transplantation) followed by analysis of TLR4 expression, EGFP, apoptosis and expression of bFGF and FSTL1. Compared with control group (TLR4 concentration 2.86 pg/5×105 cells/mL). The expression of TLR4 in BMSCs group (25.24 pg/5×105 cells/mL) and transfection group (31.55 pg/5×105 cells/mL) was significantly increased (P <0.05), and it was more significant in transfection group. The myocardial tissue of rats in control group produced a large number of scars, hypertrophy and hyperplasia of myocardial cells accompanied by a large number of necrosis; The scar tissue of the myocardium in BMSCs group and transfection group decreased, and viable myocardium increased, with more significant effect in transfection group. Control group showed a large number of blue collagen fibers in the infarction area of left ventricle, which were in the shape of cords, and part of the collagen fibers were fused. The blue collagen fibers in the control group and the transfection group were significantly reduced. Compared with control group, BMSCs group had lower apoptosis, and increased bFGF and FSTL1 levels (P <0.05). Compared with BMSCs group, the apoptosis rate of myocardial cells was decreased, and the levels of bFGF and FSTL1 were increased (P < 0.05). In conclusion, transplantation of BMSCs modified with TLR4 can increase bFGF and FSTL1 levels, reduce the rate of myocardial apoptosis and improve the myocardial pathological tissue, thus playing a therapeutic role.

Investigation of the effect of 8 weeks of high-intensity interval training and berberine supplementation on some echocardiography and electrocardiogram indices following myocardial ischemia-reperfusion in rats.

Myocardial ischemia leads to left ventricular (LV) dysfunction and cardiac arrhythmia. The present research was conducted with the aim to explore echocardiography changes and electrocardiogram parameters of the hearts of rats with ischemia-reperfusion injury (IRI). The study subjects included 50 male Wistar rats) 8-10 weeks), which were divided into 5 groups (1: trained, 2: supplemented, 3: combined (training and supplementation), 4: sham, and 5: control). High-intensity interval training ý(HIIT) was performed for 8 weeks, 5 sessions per week. Rats belonging to groups 2 and 3 received 10 mg/kg berberine. Finally, after 48 hours, electrocardiogram and echocardiography were performed on all rats. Moreover, myocardial ischemia was performed by descending coronary artery ligation for 30 minutes. There were significant differences between the 5 groups in terms of the volumes and dimensions of LV end-systolic dimension (LVSD), LV end-diastolic dimension (LVDD)ý, fractional shortening cardiac output, ejection fraction (EF), stroke volume (SV), ventricular tachycardia (VT), and ventricular ectopic beats (VEBs) episodes, duration of VTs, and ECG parameters (P ≤ 0.05). Berberine supplementation and HIIT, as preconditioning agents, can possibly prevent the elevation of EF and fractional shortening, the reduction of cardiac output and SV, and arrhythmia improvement after myocardial IRI. Finally, these changes result in increased LV function and decreased mortality in rats with myocardial IRI.

Protective Effect of Sufentanil on Myocardial Ischemia-Reperfusion Injury in Rats by Inhibiting Endoplasmic Reticulum Stress.

Objective Sufentanil is the most common drug in clinical practice for the treatment of ischemic heart disease. This study is to investigate the protective mechanism of sufentanil on rat myocardial ischemia-reperfusion (I/R) injury. Methods A rat I/R model was established by ligating the left anterior descending coronary artery. A total of 24 SD male rats were enrolled and divided randomly into the control group, I/R group, sufentanil group (SUF; 3 μg/kg), and diltiazem group (DLZ; 20 mg/kg; positive control). The rat hearts were subjected to 30 min of ischemia followed by 120 min of reperfusion. Subsequently, hemodynamics, pathological changes of myocardial tissue, serum biochemical parameters, oxidative stress factors, the level of serum inducible nitric oxide synthases (iNOS), interleukin-6 (IL-6), and other bioactive factors were analyzed in the rats. Result Compared with the I/R group, sufentanil significantly improved cardiac action, myocardial fiber, and cardiomyocyte morphology and reduced inflammatory cell infiltration in rats in the SUF group. And the level of creatine kinase isoenzyme (CK-MB), troponin (cTn), lactate dehydrogenase (LDH), malondialdehyde (MDA), iNOS, and IL-6 was significantly declined in the serum of SUF group, while the activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were significantly activated in the myocardial tissues. In addition, sufentanil also significantly decreased the protein expression of GRP78, CHOP, Caspase 12, and ATF6 in the myocardial tissue of the SUF group. Conclusion Sufentanil has a significant protective activity on myocardial I/R injury in rats, the mechanism of which may be associated with the inhibition of endoplasmic reticulum stress and oxidative stress.

Fasudil on Myocardial Injury in Rats with Myocardial Ischemia and Reperfusion through Rho-ROCK Signal Pathway

Cardiovascular diseases are very harmful to human life and health. Reperfusion therapy is a standard method to treat cardiovascular diseases and has achieved high clinical effects. However, this treatment method is likely to cause myocardial ischemia-reperfusion injury. It has been reported that the Rho kinase inhibitor fasudil can interfere with cardiomyocyte apoptosis through the Rho-ROCK signaling pathway, so it is often used to treat cardiovascular diseases. The essay aims to research this specific influence of fasudil on cardiac damage in myocardial ischemia-reperfusion mouses through the Rho-ROCK signal path and its related mechanisms. Forty rats were taken as the research object, and the mouses were separated into control clusters. In the observation cluster of fasudil, the rat heart device was perfused by surgery. The rat coronary artery was ligated for 20 minutes to make the rat myocardial ischemia. Then, the ligation was loosened for myocardial perfusion to create a rat myocardial ischemia-reperfusion model. Observation group rats were perfused with quantitative fasudil, 80 minutes after ischemia-reperfusion, the ultrastructural changes and myocardial ischemic area of the rat myocardium were observed under a microscope, and the dynamic changes of the mouse heart were examined by flow cytometry. The PCR fluorescence method was used to explore the outlook layer of Rho-ROCK kinase activity to detect rat cardiomyocyte apoptosis. It is shown that under this intervention of fasudil, this expression level of Rho-ROCK kinase activity in the observation group was reduced by 18.3%, the myocardial cell apoptosis rate was decreased by 26.4%, and one area of myocardial ischemia can be reduced by 32.5%. The ultrastructure of the new object in rats is improved, and the left ventricular diastolic and systolic effect is enhanced. Therefore, the fasudil may decrease cardiac ischemia and focus on injured Rho-ROCK signal path activity.

Remifentanil Anesthesia on the Expression of Apoptosis-Related Proteins Bcl-2 and Bax in Rat Myocardial Cells with Ischemia-Reperfusion Injury

Ischemia-reperfusion damage to the myocardium is inevitable. This study mainly explored the effect of remifentanil anesthesia on the expression of apoptosis-related proteins Bcl-2 and Bax in rat myocardial ischemia-reperfusion injury. Select 48 mice (n=6). First, prepare solutions of different concentrations of remifentanil. A model of ischemia-reperfusion cardiomyocytes was established, and 6 slices of tissue were taken from each specimen, and the positive cells were observed with an optical microscope and magnified 100 times. Bcl-2 and Bax were positive in the cytoplasm and yellowish-brown particles in the inner membrane. According to the distribution of positive cells, randomly select 3 clear fields of view from each part, count the number of positive cells in each field, and then take the average of the proportion of positive cells to get Bcl-2 or Bax protein-positive Index (PEI). Comparison of mRNA levels in each group: Compared with the R3 group, the ratio of the M, R1, and R2 groups increased, and the mRNA expression level of the M group increased almost 3 times, P<0.05. The results of the study show that remifentanil reduces the mortality of myocardial cells by regulating the appearance of Bcl-2 and Bax proteins, and has a certain protective effect on the rat heart during myocardial ischemia and reperfusion. There is no statistically significant difference in the protective effect of remifentanil on myocardial ischemia-reperfusion.

Britanin relieves ferroptosis-mediated myocardial ischaemia/reperfusion damage by upregulating GPX4 through activation of AMPK/GSK3β/Nrf2 signalling

Context Ferroptosis was described as an important contributor to the myocardial ischaemia/reperfusion (MIR) injury, and britanin (Bri) was reported to exert antitumor and anti-inflammatory activities. Objective Our study explores the effect and mechanism of Bri on MIR damage. Materials and methods The rat model of MIR was established by ligation of the left anterior descending coronary artery. Male Sprague–Dawley (SD) rats were divided into three groups: sham group (n = 6), MIR group (n = 6) and MIR + Bri group (n = 6; 50 mg/kg). Rats were intragastrically pre-treated with Bri or normal saline once daily for 3 days. To further verify the role and mechanism of Bri, H9C2 cells were subjected to hypoxia plus reoxygenation (H/R) to induce the in vitro model of MIR. Results Compared with MIR rats, Bri significantly decreased infarct area (22.50% vs. 38.67%), myocardial apoptosis (23.00% vs. 41.5%), creatine phosphokinase (0.57 U/mL vs. 0.76 U/mL), and lactate dehydrogenase levels (3.18 U/mL vs. 5.17 U/mL), concomitant with alleviation of ferroptosis. Mechanistically, Bri treatment induced the activation of the adenosine monophosphate activated protein kinase (AMPK)/glycogen synthase kinase 3β (GSK3β)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in vivo. In addition, the AMPK/GSK3β/Nrf2 pathway participated in the regulation of glutathione peroxidase 4 (GPX4) expression, and silencing of Nrf2 attenuated the effect of Bri on H/R-induced cell injury. Discussion and conclusions Bri protected against ferroptosis-mediated MIR damage by upregulating GPX4 through activation of the AMPK/GSK3β/Nrf2 signalling, suggesting that Bri might become a novel therapeutic agent for MIR.

Retraction.

Retraction: "Anti-Apoptotic Effect of MicroRNA-30b in Early Phase of Rat Myocardial Ischemia-Reperfusion Injury Model," Chun-Li Song, Bin Liu, Jin-Peng Wang, Bei-Lin Zhang, Ji-Chang Zhang, Li-Yan Zhao, Yong-Feng Shi, Yang-Xue Li, Guan Wang, Hong-Ying Diao, Qian Li, Xin Xue, Jun-Duo Wu, Jia Liu, Yun-Peng Yu, Dan Cai, and Zhi-Xian Liu, J Cell Biochem. 2015; 2610-2619: The above article, published online on 28 April 2015 in Wiley Online Library (https://onlinelibrary.wiley.com/doi/10.1002/jcb.25208) has been retracted by agreement between the authors, the journal's Editor in Chief, Prof. Dr. Christian Behl, and Wiley Periodicals LLC. The retraction has been agreed because the authors stated that unintentional errors occurred during the research process, and the experimental results cannot be verified. Thus, the conclusions are considered to be invalid. The authors apologize for the unintentional errors.

NPAS2 ameliorates myocardial ischaemia/reperfusion injury in rats via CX3CL1 pathways and regulating autophagy.

Background: Myocardial ischemia/reperfusion (I/R) injury is common during the treatment of cardiovascular diseases. Neuronal PAS Domain Protein 2 (NPAS2) is one of the core genes that control the rhythm of the biological clock. NPAS2 also regulates the biological rhythm.Results: The rat I/R model showed that the expression of NPAS2 decreased with the increase of reperfusion time. Overexpressing NPAS2 adenovirus (ad-NPAS2) was injected into IR rat which demonstrated that ad-NPAS2 ameliorated rats I/R injury. A hypoxia/reoxygenation (H/R) model in rat cardiomyocytes showed that ad-NPAS2 inhibited cardiomyocyte apoptosis. Co-Immunoprecipitation results showed that there is an interaction between NPAS2 and Cry2. Knockdown of Cry2 aggravated the cardiomyocyte apoptosis induced by H/R. Additionally, NPAS2 directly act on the promoter region of CX3CL1. Knockdown of CX3CL1 reverse the protective effect of ad-NPAS2 on rat myocardial ischemia-reperfusion injury and H/R-induced cardiomyocyte apoptosis. CX3CL1 also regulates autophagy through the downstream AKT/mTOR pathway.Conclusions: research demonstrated that overexpression of NPAS2 interacts with Cry2 and promotes the transcriptional activity of CX3CL1. Moreover, overexpression of NPAS2 regulates the downstream AKT/mTOR pathway to inhibit autophagy in order to improve rat cardiac I/R injury.

Effects of Aspirin on Myocardial Ischemia-Reperfusion Injury in Rats through STAT3 Signaling Pathway.

Objective To investigate the role and mechanism of aspirin in myocardial injury induced by myocardial ischemia-reperfusion in rats through STAT3 signaling pathway. Methods Sixty rats were randomly divided into three groups: the sham operation group, MI/R group, and MI/R+aspirin group (aspirin group). The rats in the sham operation group did not ligate the LAD coronary artery, while the aspirin group ligated the LAD coronary artery, which caused the suture to be loosened after 30 minutes ischemia, and 60 mg/kg aspirin was injected into the tail vein 10 minutes before reperfusion. After three hours of reperfusion, the ultrasound system was used to collect hemodynamic parameters, including ejection fraction (EF%), shortening fraction (FS%), and left ventricular end-systolic pressure (LVESP%) and left ventricular end-diastolic pressure (LVEDP%). Finally, the rats were euthanized; then, blood samples were taken for biochemical examination, myocardial tissue was collected, and the left ventricle was used for subsequent experiments. The gene expression levels of Bax and Bcl-2 were detected by PCR. The protein expression levels of Bcl-2, Bax, p-JAK2, total JAK2, p-STAT3, and total STAT3 were detected by Western blot. Results Compared with the sham operation group and the aspirin group, the area of myocardial infarction in the MI/R was significantly increased (p < 0.05). In terms of hemodynamic parameters, LVEDP was significantly elevated in the MI/R group. The results of PCR showed that compared with the MI/R group, the mRNA expression of Bax in the aspirin group was significantly decreased, while that of Bcl-2 was significantly increased (p < 0.05). Western blot analysis showed that compared with the MI/R group, aspirin pretreatment significantly increased the expression levels of p-STAT3 and p-JAK2 (p < 0.05). Conclusion The mechanism of aspirin preconditioning to protect the heart from MI/R injury appears to be related to JAK2/STAT3 and related to the activation of the signaling pathway.

MiR-451 on Myocardial Ischemia-Reperfusion in Rats by Regulating AMPK Signaling Pathway.

Myocardial infarction is the main cause of death in patients with coronary heart disease. At present, the main method to treat cardiovascular disease is perfusion therapy. Myocardial ischemia-reperfusion will inevitably lead to reperfusion injury, which is also a major problem in the treatment of cardiovascular diseases. It has been reported that mir-451 in microRNA family participates in the protection of myocardial ischemia-reperfusion by regulating AMPK. The aim of this study was to investigate the effect of mir-451 on myocardial ischemia-reperfusion in rats by regulating AMPK signaling pathway. Sixty adult male rats were selected to establish myocardial ischemia-reperfusion animal model by ligating and loosening coronary artery. The expression level of mir-451 was regulated by injection of mir-451 virus vector and antibody, and the effect of increased or decreased mir-451 expression level on the activity of AMPK signaling pathway was detected. The myocardial infarct area and apoptosis rate of myocardial tissue were detected after 75 min ischemia-reperfusion. The results showed that when the expression level of mir-451 decreased by 15.7%, the activity index of AMPK signaling pathway was increased by 18.3%, the infarct area was reduced by 22.4%, and the apoptosis rate of myocardial cells was decreased by 25.2%. At the same time, the pathological structure of myocardial tissue was improved. Therefore, mir-451 is an inhibitor gene of AMPK signaling pathway. Reducing the expression of mir-451 can enhance the activity of AMPK signal pathway, and the increase of AMPK signal pathway activity is beneficial to reduce myocardial ischemia-reperfusion injury.

Cannabidiol-mediated RISK PI3K/AKT and MAPK/ERK pathways decreasing reperfusion myocardial damage.

Myocardial ischemia continues to be the first cause of morbimortality in the world; the definitive treatment is reperfusion; however, this action causes additional damage to ischemic myocardial tissue; this forces to seek therapies of cardioprotection to reduce this additional damage. There are many cardioprotective agents; within these, cannabinoids have shown to have beneficial effects, mainly cannabidiol (CBD). CBD is a non psychoactive cannabinoid. To evaluate the effect in experimental models of CBD in myocardial ischemia reperfusion in rats, twelve‐week‐old male rats have been used. The animals were divides in 3 groups: control(C), ischemia reperfusion (IR) and CBD pretreatment (1/day/5mg/kg /10days). Langendorff organ isolate studies were performed, and the area of infarction was assessed with triphenyl tetrazolium, in addition to molecular analysis of AT1 and AT2 receptors and Akt and Erk proteins and their phosphorylated forms related to RISK pathways. It was observed that there is an improvement with the use of CBD increasing inotropism and cardiac lusitropism, improving considerably the cardiovascular functionality. These could be related to the reduction of the area of infarction and activation of the AT2 receptor and the RISK pathway with absence of activation of the AT2 receptor (these could relate the reduction of the infarct area and the restoration of cardiovascular function with the activation of the AT2 receptor and the RISK pathway with the absence of activation of the AT2 receptor). The use of cannabinoids was shown to have beneficial effects when used as a treatment for myocardial reperfusion damage.