Myocardial MDA Research Articles

Integrating bioinformatics and ferroptosis to reveal the protective mechanism of Astragaloside IV on chronic heart failure rats

Ferroptosis is an important pathological mechanism of chronic heart failure (CHF). This study aimed to investigate the protective mechanism of Astragaloside IV (AS-IV) on CHF rats by integrating bioinformatics and ferroptosis. CHF-related targets and ferroptosis-related targets were collected. After the intersection, the common targets were obtained. The PPI network of the common targets was constructed, and topological analysis of the network was carried out. The target with the highest topological parameter values was selected as the key target. The key target p53 was obtained through bioinformatics analysis, and its molecular docking model with AS-IV was obtained, as well as molecular dynamics simulation analysis. The rat models of CHF after myocardial infarction were established by ligation of left coronary artery and treated with AS-IV for 4 weeks. AS-IV treatment significantly improved cardiac function in CHF rats, improved cardiomyocyte morphology and myocardial fibrosis, reduced mitochondrial damage, decreased myocardial MDA and Fe2+ content, increased GSH content, inhibited the expression of p53 and p-p53, and up-regulated the expression of SLC7A11 and GPX4. In conclusion, AS-IV improved cardiac function in CHF rats, presumably by regulating p53/SLC7A11/GPX4 signaling pathway and inhibiting myocardial ferroptosis.

Molecular mechanism of Danxiong Tongmai Granules in treatment of coronary heart disease.

Danxiong Tongmai Granules (DXTMG) are widely utilized in treating coronary heart disease (CHD) in China. This study aims to explore the molecular mechanisms underlying the therapeutic effects of DXTMG on CHD by employing a network pharmacology approach, complemented with experimental validation. Traditional Chinese Medicine (TCM) compounds and targets were identified via searches in the BATMAN-TCM database, and the GeneCards database was used to obtain the main target genes involved in CHD. We combined disease targets with the drug targets to identify common targets. The "TCM-compound-target" network was plotted using Cytoscape 3.7.2 software and a protein-protein interaction (PPI) network was constructed using the STRING database from which core targets were obtained. Gene ontology (GO) function analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed for common drug-disease targets using R Version 4.0.4 (64 bit) software. Molecular docking of core protein-small molecule ligand interaction was modeled using AutoDock software. A molecular dynamics simulation was conducted on the optimal protein-small molecule complex identified through molecular docking, using Amber18 software. The rat model for myocardial ischemia was established through pre-gavage administration of DXTMG, followed by dorsal hypodermic injection of isoprenaline. Myocardial tissues from the rats were analyzed using hematoxylin and eosin (HE) staining and Masson's trichrome staining. Relevant targets were validated by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. 162 potential targets of DXTMG involved in CHD were identified. These included INS, ALB, IL-6 and TNF according to PPI network studies. GO enrichment analysis identified a total of 3365 GO pathways, including 3049 biological process pathways (BP) concerned with the heart and circulatory system; 109 cellular component (CC) pathways, including cation channels and membrane rafts and 207 molecular function (MF) pathways related to receptor ligands and activators. KEGG analysis revealed a total of 137 pathways (P < 0.05), including those related to AGE-RAGE signaling associated with diabetic complications, fluid shear stress and atherosclerosis. The results of molecular docking and molecular dynamics simulations demonstrated the robust binding affinity between the compounds and target proteins. Animal experiment findings indicated that, compared with the model group, the DXTMG group effectively ameliorated inflammation and fibrosis in rat myocardial tissues, reduced LDH, cTn-I, and MDA levels (P < 0.05, P < 0.01), elevated SOD and GSH-PX levels (P < 0.05), and reduced the percentage of positive area for IL-6 and TNF-α (P < 0.05). This study preliminarily suggests that DXTMG can modulate oxidative stress, inflammation response, and cardiomyocyte regulation, thereby mitigating the onset and progression of CHD.

The role of MOTS-c-mediated antioxidant defense in aerobic exercise alleviating diabetic myocardial injury.

Myocardial remodeling and dysfunction are commonly observed in type 2 diabetes mellitus (T2DM). Aerobic exercise can partly alleviate diabetes-induced myocardial dysfunction through its antioxidant actions. MOTS-c is a potential exercise mimic. This study aimed to investigate the effects of MOTS-c on improving diabetic heart function and its mechanism and to identify whether MOTS-c improved antioxidant defenses due to aerobic exercise. Herein, we established a rat model of T2DM induced by high-fat diet combined with a low-dose streptozotocin injection. Interventions were performed using intraperitoneal injections of MOTS-c (i.p. 0.5mg/kg/day, 7days/week) or aerobic exercise training (treadmill, 20 m/min, 60 min/day, 5days/week) for 8 weeks. Myocardial ultrastructure was assessed using transmission electron microscopy (TEM), myocardial lipid peroxidation levels (MDA), superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT) levels were assessed using colorimetric methods, and molecular analyses including MOTS-c, Kelch-like ECH-associated protein 1 (Keap1), Nuclear factor E2-related factor 2 (Nrf2), adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)and phospho-AMPK (p-AMPK) were examined using Western blot. The results showed that MOTS-c, with or without exercise, reduced myocardial ultrastructural damage and improved glucolipid metabolism and cardiac function in T2DM. Furthermore, MOTS-c increased antioxidant markers such as SOD, CAT, and the protein expression of myocardial MOTS-c, Keap1, Nrf2, and p-AMPK. MOTS-c with exercise treatment reduced myocardial MDA and increased p-AMPK significantly comparing to only exercise or MOTS-c alone. Our findings suggest that MOTS-c may be a helpful supplement for overcoming exercise insufficiency and improving myocardial structure and function in diabetes.

Decrease of Cellular Communication Network Factor 1 (CCN1) Attenuates PTZ-Kindled Epilepsy in Mice.

To investigate the molecular mechanism of communication network factor 1 (CCN1) regulating pentylenetetrazol (PTZ)-induced epileptogenesis, deepen the understanding of epilepsy seizure pathogenesis, and provide new drug action targets for its clinical prevention and treatment. Differentially expressed genes (DEGs) on microarrays GSE47516 and GSE88992 were analyzed online using GEO2R. Pathway enrichment and protein-protein interaction network (PPI) analysis of DEGs were carried out using Metascape. Brain tissue samples of severe traumatic brain injury patients (named Healthy group) and refractory epilepsy patients (named Epilepsy group) were obtained and analyzed by qRT-PCR and immunohistochemistry (IHC) staining. A PTZ-induced epilepsy mouse model was established and verified. Morphological changes of neurons in mouse brain tissue were detected using hematoxylin and eosin (HE) staining. qRT-PCR was conducted to detect the mRNA expressions of apoptosis-associated proteins Bax, Caspase-3 and bcl2. TUNEL staining was performed to detect brain neuron apoptosis. The levels of myocardial enzymology, GSH, MDA and ROS in blood of mouse were detected by biochemical assay. CCN1 expression was increased in epilepsy brain tissue samples. CCN1 decreasing effectively prolongs seizure incubation period and decreases seizure duration. Silencing of CCN1 also reduces neuronal damage and apoptosis, decreases mRNA and protein expression of proapoptotic proteins Bax and Caspase-3, increases mRNA expression of antiapoptotic protein Bcl2. Moreover, decrease of CCN1 decreases myocardial enzymatic indexes CK and CK-MB levels, reduces myocardial tissue hemorrhage, and relieves oxidative stress response in hippocampal and myocardial tissue. CCN1 expression is increased in epileptic samples. CCN1 decreasing protects brain tissue by attenuating oxidative stress and inhibiting neuronal apoptosis triggered by PTZ injection, which probably by regulating Nrf2/HO-1 pathway.

Paeonol improves angiotensin II-induced cardiac hypertrophy by suppressing ferroptosis

The aim of this study was to investigate the protective effect of paeonol (pae) on an angiotensin II (AngII)-induced cardiac hypertrophy mouse model. First, AngII mouse models were constructed and randomly grouped into the control (con), AngII, and AngII + Pae groups. Compared with that in the blank group, the surface area of myocardial cells in the AngII group increased significantly. In contrast to that in the AngII group, the cardiomyocyte surface area in the Pae group was significantly reduced. Ultrasound results showed that the myocardial function of mice in the AngII group was decreased compared with that in the Con group, while the myocardial function of mice in the Pae treatment was significantly improved. Moreover, the Fe2+ and lipid peroxide levels of primary cardiomyocytes were significantly increased after treatment with AngII and were significantly decreased after the addition of Pae. Compared with those in the Con group, cristae were reduced and the outer membrane was lost in the myocardial tissues of the AngII group, and myocardial MDA, ROS, and Fe2+ levels were increased. However, myocardial damage was significantly alleviated after Pae treatment, and myocardial MDA, ROS, and Fe2+ levels were reduced. Moreover, in myocardial tissue, AngII reduced the protein levels of xCT and GPX4, while the levels of both xCT and GPX4 were increased after Pae treatment. In conclusion, Pae protected the hearts of AngII mice by upregulating the protein expression of xCT and GPX4 and resisting AngII-induced ferroptosis in cardiomyocytes.

Dexmedetomidine postconditioning attenuates myocardial ischemia/reperfusion injury by activating the Nrf2/Sirt3/SOD2 signaling pathway in the rats

ABSTRACTObjectivesTo observe the protective effects of dexmedetomidine (Dex) postconditioning on myocardial ischemia/reperfusion injury (IRI) and to explore its potential molecular mechanisms.MethodsOne-hundred forty-seven male Sprague-Dawley rats were randomly divided into five groups receiving the different treatments: Sham, ischemia/reperfusion (I/R), Dex, Brusatol, Dex + Brusatol. By the in vivo rat model of myocardial IRI, cardioprotective effects of Dex postconditioning were evaluated by assessing serum CK-MB and cTnI levels, myocardial HE and Tunel staining and infarct size. Furthermore, the oxidative stress-related markers including intracellular ROS level, myocardial tissue MDA level, SOD and GSH-PX activities were determined.ResultsDex postconditioning significantly alleviated myocardial IRI, decreased intracellular ROS and myocardial tissue MDA level, increased SOD and GSH-PX activities. Dex postconditioning significantly up-regulated myocardial expression of Bcl-2, down-regulated Bax and cleaved caspase-3 and decreased cardiomyocyte apoptosis rate. furthermores, Dex postconditioning promoted Nrf2 nuclear translocation, increased myocardial expression of Sirt3 and SOD2 and decreased Ac-SOD2. However, brusatol reversed cardioprotective benefits of Dex postconditioning, significantly decreased Dex-induced Nrf2 nuclear translocation and reduced myocardial expression of Sirt3 and SOD2.ConclusionsDex postconditioning can alleviate myocardial IRI by suppressing oxidative stress and apoptosis, and these beneficial effects are at least partly mediated by activating the Nrf2/Sirt3/SOD2 signaling pathway.

Spinacetin alleviates doxorubicin-induced cardiotoxicity by initiating protective autophagy through SIRT3/AMPK/mTOR pathways

BackgroundDoxorubicin-induced myocardiopathy is a massive obstacle in administering chemotherapeutic drugs in cancer patients. PurposesIn the present study, we aim to investigate the effects of spinacetin, a flavonoid glycoside, on doxorubicin-induced cardiotoxicity. Study designThe doxorubicin-induced cardiotoxicity mice model was established to evaluate the cardioprotective effects of SP. The H9C2 cell line was used to study SP's potential mechanisms of action. Dexrazoxane (180 mg/kg) was used as the positive control. MethodsThe CCK-8 cell proliferation assay, hematoxylin and eosin (HE) staining, detection of serum biomarkers, flow cytometry for apoptosis, dansylcadaverine (MDC) staining, and Western blot for crucial molecules were conducted in the present study. ResultsSP significantly increased the survival rate of primary cardiomyocytes and decreased the serum LDH, CK-MB, TrT, and myocardial MDA level. The apoptosis of cardiomyocytes significantly decreased by SP, with upregulation of autophagy. In the H9C2 cell line, SP protects the cells from doxorubicin-induced cytotoxicity, decreases apoptosis, and increases autophagy. The subsequent mechanism study showed that the activation of AMPK/mTOR signaling was involved in the protective effects of SP on doxorubicin-induced cardiotoxicity through upregulating the expression level of SIRT3. ConclusionWe concluded that SP could protect against doxorubicin-induced cardiotoxicity both in vitro and in vivo by initiating protective autophagy through SIRT3/AMPK/mTOR pathways, which has not been reported previously. SP could be treated as a potential candidate for cardioprotective usage during chemotherapy. The further clinical study is still urgently needed to investigate the safety and effectiveness of SP in patients.

Diabetes impairs the protective effects of sevoflurane postconditioning in the myocardium subjected to ischemia/ reperfusion injury in rats: important role of Drp1

BackgroundSevoflurane postconditioning (SevP) effectively relieves myocardial ischemia/reperfusion (I/R) injury but performs poorly in the diabetic myocardium. Previous studies have revealed the important role of increased oxidative stress in diabetic tissues. Notably, mitochondrial fission mediated by dynamin-related protein 1 (Drp1) is an upstream pathway of reactive oxygen production. Whether the ineffectiveness of SevP in the diabetic myocardium is related to Drp1-dependent mitochondrial fission remains unknown. This study aimed to explore the important role of Drp1 in the diabetic myocardium and investigate whether Drp1 inhibition could restore the cardioprotective effect of SevP.MethodsIn the first part of the study, adult male Sprague-Dawley rats were divided into 6 groups. Rats in the diabetic groups were fed with high-fat and high-sugar diets for 8 weeks and injected intraperitoneally with streptozotocin (35 mg/kg). Myocardial I/R was induced by 30 min of occlusion of the left anterior descending branch of the coronary artery followed by 120 min of reperfusion. SevP was applied by continuous inhalation of 2.5 % sevoflurane 1 min before reperfusion, which lasted for 10 min. In the second part of the study, we applied mdivi-1 to investigate whether Drp1 inhibition could restore the cardioprotective effect of SevP in the diabetic myocardium. The myocardial infarct size, mitochondrial ultrastructure, apoptosis index, SOD activity, MDA content, and Drp1 expression were detected.ResultsTTC staining and TUNEL results showed that the myocardial infarct size and apoptosis index were increased in the diabetic myocardium. However, SevP significantly alleviated myocardial I/R injury in the normal myocardium but not in the diabetic myocardium. Additionally, we found an elevation in Drp1 expression, accompanied by more severe fission-induced structural damage and oxidative stress in the diabetic myocardium. Interestingly, we discovered that the beneficial effect of SevP was restored by mdivi-1, which significantly suppressed mitochondrial fission and oxidative stress.ConclusionsOur study demonstrates the crucial role of mitochondrial fission dependent on Drp1 in the diabetic myocardium subjected to I/R, and strongly indicates that Drp1 inhibition may restore the cardioprotective effect of SevP in diabetic rats.

Exercise and Stevia Rebaudiana (R) Extracts Attenuate Diabetic Cardiomyopathy in Type 2 Diabetic Rats: Possible Underlying Mechanisms.

In the current work, we studied the effects of exercise and stevia rebaudiana (R) extracts on diabetic cardiomyopathy (DCM) in type 2 diabetic rats and their possible underlying mechanisms. Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group, b) DM group, type 2 diabetic rats received 2 ml oral saline daily for 4 weeks, c) DM+ Exercise, type 2 diabetic rats were treated with exercise for 4 weeks and d) DM+ stevia R extracts: type 2 diabetic rats received methanolic stevia R extracts. By the end of the experiment, serum blood glucose, HOMA-IR, insulin and cardiac enzymes (LDH, CK-MB), cardiac histopathology, oxidative stress markers (MDA, GSH and CAT), myocardial fibrosis by Masson trichrome, the expression of p53, caspase-3, α-SMA and tyrosine hydroxylase (TH) by immunostaining in myocardial tissues were measured. T2DM caused a significant increase in blood glucose, HOMA-IR index, serum CK-MB and LDH, myocardial damage and fibrosis, myocardial MDA, myocardial α-SMA, p53, caspase-3, Nrf2 and TH density with a significant decrease in serum insulin and myocardial GSH and CAT (p< 0.05). On the other hand, treatment with either exercise or stevia R extracts significantly improved all studied parameters (p< 0.05). Moreover, the effects of stevia R was more significant than exercise (p< 0.05). Both exercise and methanolic stevia R extracts showed cardioprotective effects against DCM and Stevia R offered more cardioprotective than exercise. This cardioprotective effect of these lines of treatment might be due to attenuation of oxidative stress, apoptosis, sympathetic nerve density and fibrosis and upregulation of the antioxidant transcription factor, Nrf2.

2137-PUB: Exercise and Stevia R. Extracts Attenuate Diabetic Cardiomyopathy in Type 2 Diabetic Rats via Upregulation of Nrf2 and Suppression of Oxidative Stress, Fibrosis, Apoptosis, and Sympathetic Overactivity

Objectives: In the current work, we studied the effects of exercise and stevia extracts on diabetic cardiomyopathy in type 2 diabetic rats and their possible underlying mechanisms. Methods: Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group, b) DM group, type 2 diabetic rats received 2ml oral saline daily for 4 weeks, c) DM+ Exercise, type 2 diabetic rats were treated with exercise for 4 weeks and d) DM+ stevia extracts: type 2 diabetic rats received methanolic stevia extracts. By the end of experiment, serum blood glucose, HOMA-IR, insulin and cardiac enzymes (LDH, CK-MB), cardiac histopathology, oxidative stress markers (MDA, GSH and CAT), myocardial fibrosis by Masson trichrome, the expression of p53, α-SMA and tyrosine hydroxylase (TH) by immunostaining in myocardial tissues were measured. Also, the expression of nuclear factor erythroid-like factor 2 (nrf2) was measured in myocardial tissues. Results: We found that T2DM caused significant increase in blood glucose, HOMA-IR index, serum CK-MB and LDH, myocardial damage and fibrosis, myocardial MDA, myocardial α-SMA, p53, nrf2 and TH density with significant decrease in serum insulin and myocardial GSH and CAT. On the other hand, treatment with either exercise or stevia extracts caused in significant improvement in studied parameters. Conclusions: exercise and methanolic stevia extracts have cardioprotective effects against DCM, which might be due to attenuation of fibrosis, oxidative stress, p53, TH and upregulation of nrf2. Moreover, stevia extracts offered more protective effect than exercise. Disclosure A. Hussein: None. E.A. Eid: None. M. Taha: None. L. Lashin: None.

442-P: Comparative Study of the Effects of GLP-1 Analog and SGLT2 Inhibitor against Diabetic Cardiomyopathy in Type 2 Diabetic Rats: Possible Underlying Mechanisms

Objectives: In the present study we investigated the possible cardioprotective effects of GLP-1 and SGLTi against diabetic cardiomyopathy (DCM) in type 2 diabetic rats and the mechanisms underlying these effects. Methods: 32- male Sprague Dawley rats were randomly subdivided into 4 equal groups; a) control group, b) DM group, type 2 diabetic rats received 2ml oral saline daily for 4 weeks, c) DM+ GLP-1, type 2 diabetic rats were treated with GLP-1 analogue (liraglutide) at a dose of 75 µg/kg via S.C. injection for 4 weeks and d) DM+ SGLTi: type 2 diabetic rats received SGLT2 inhibitor (dapagliflozin) at a dose of 1mg/kg via oral gastric gavage. By the end of treatment (4 weeks), serum blood glucose, HOMA-IR, insulin and cardiac enzymes (LDH, CK-MB) were measured. Also, the cardiac histopathology, myocardial oxidative stress markers (MDA, GSH and CAT) and norepinephrine (NE), myocardial fibrosis, the expression of caspase-3, TGF-β, TNF-α and tyrosine hydroxylase (TH) in myocardial tissues were measured. Results: T2DM caused significant increase in serum glucose, HOMA-IR index, serum CK-MB and LDH (p&amp;lt; 0.05). This was associated with significant myocardial damage and fibrosis, elevation of myocardial MDA, NE with upregulation of myocardial caspase-3, TNF-α, TGF-β and TH and significant decrease in serum insulin and myocardial GSH and CAT (p&amp;lt;0.05). Administration of either GLP-1 analog or SGLTi caused in significant improvement in all studied parameters (p&amp;lt; 0.05). Conclusions: GLP-1 and SGLTi exhibited cardioprotective effects against DCM in type 2 diabetic rats. SGLTi showed more cardioprotective effect than GLP-1. The cardioprotective actions of these agents might be due to attenuation of fibrosis, oxidative stress, apoptosis (caspase-3), sympathetic nerve activity and inflammatory cytokines (TNF-α and TGF-β). Disclosure E.A. Eid: None. A. Hussein: None. L. Lashin: None. M. Taha: None.

Probucol recovers pathological damage in viral Myocarditis through improvement of myocardium-related proteins

This study explored the effects of probucol on myocardial injury, oxidative stress, and Cav-3 and Smad3 expression in myocardial tissues by establishing VMC rat models, in order to provide a basis for exploring the mechanism of probucol in treatment of VMC. Sixty rats were randomly divided into control group, model group, probucollowdose group, andprobucol highdose group, with 15 in each group. Except for the control group, rats in each group were intraperitoneally injected coxsackievirus B3 diluent (0.2 ml) to replicate VMC models every 4 days. The results showed that Caspase-3 and Caspase-9, myocardial enzymes, cTn I, and MDA levels in the model group significantly increased (P < 0.05), while the SOD level significantly decreased (P < 0.05); and after probucol treatment, Caspase-3 and Caspase-9, myocardial enzymes, cTn I and MDA levels significantly decreased (P < 0.05), and the SOD level significantly increased (P < 0.05). Compared with the control group, there was an increase in myocardial fibers with significant lesions in the model group, and the pathological scores and the mRNA and protein expression levels of Cav-3 and Smad3 in myocardial cells significantly increased (P < 0.05). Compared with the control group, the myocardial tissue lesions were improved in the probucol low dose group and highdose group, and the pathological scores and the mRNA and protein expression levels of Cav-3 and Smad3 in myocardial cells were significantly reduced (P < 0.05). In conclusion, probucol can significantly improve the pathological damage of myocardial tissue in VMC rats, and its mechanism may be related to improving the expression of myocardium-related proteins Caspase-3 and Caspase-9, inhibiting oxidative stress response, and down-regulating Cav-3 and Smad3 gene expression in myocardial tissue of VMC rats.

Blockade of Renin Angiotensin System Ameliorates the Cardiac Arrhythmias and Sympathetic Neural Remodeling in Hearts of Type 2 DM Rat Model.

The present study was designed to investigate the effects of renin angiotensin system (RAS) blockade on cardiac arrhythmias and sympathetic nerve remodelling in heart tissues of type 2 diabetic rats. Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group: normal rats, b) DM group; after type 2 diabetes induction, rats received 2ml oral saline daily for 4 weeks, c) DM+ ACEi: after type 2 diabetes induction, rats were treated with enalapril (10 mg/kg, orally for 4 weeks) and d) DM+ ARBs: after type 2 diabetes induction, rats were treated with losartan (30 mg/kg, orally for 4 weeks). In type 2 diabetic rats, the results demonstrated significant prolongation in Q-T interval and elevation of blood sugar, HOMA-IR index, TC, TGs, LDL, serum CK-MB, myocardial damage, myocardial MDA, myocardial norepinephrine and tyrosine hydroxylase (TH) density with significant reduction in serum HDL, serum insulin and myocardial GSH and CAT. On the other hand, blockade of RAS at the level of either ACE by enalapril or angiotensin (Ag) receptors by losartan resulted in significant improvement in ECG parameters (Q-T), cardiac enzymes (CK-MB), cardiac morphology, myocardial oxidative stress (low MDA, high CAT and GSH) and myocardial TH density. RAS plays a role in the cardiac sympathetic nerve sprouting and cardiac arrhythmias induced by type 2 DM and its blockade might have a cardioprotective effect via attenuation of sympathetic nerve fibres remodelling, myocardial norepinephrine contents and oxidative stress.

Dexmedetomidine attenuates myocardial ischemia/reperfusion injury through regulating lactate signaling cascade in mice.

The aim of this study was to investigate the role of dexmedetomidine (Dex) in lactate signaling cascade and myocardial ischemia/reperfusion (I/R) injury in mice. The left anterior descending of the coronary artery was ligatured for 30 min and then reperfused for 6 h to induce myocardial I/R injury in mice. Heart samples were collected and the levels of lactate, SOD and MDA were measured. Infarct size and myocardium were stained with triphenyltetrazolium chloride and TUNEL, respectively. In addition, the expression levels of MCT1, cytochrome c, cleaved caspase-9 and -3 were detected by Western blot. The myocardial infarct size, lactate and MDA levels of the I/R group were significantly increased, whereas the SOD activity was decreased. However, Dex significantly reduced the myocardial infarct size, as well as lactate and MDA levels in contrast to the I/R group. Meanwhile, the SOD activity was remarkably increased. The expression levels of MCT1, cytochrome c, cleaved caspase-9 and -3 were significantly increased in the I/R group. In addition, Dex administration further increased the expression of MCT1, whereas decreased the expressions of cytochrome c, cleaved caspase-9 and -3 in contrast to the I/R group. Dex elevated the expression of mitochondrial MCT1 and inhibited oxidative stress and the activation of mitochondria-dependent apoptosis in mice. This indicated that Dex attenuated myocardial I/R injury by regulating lactate signaling cascade.

Naringenin Attenuates Myocardial Ischemia-Reperfusion Injury via cGMP-PKGIα Signaling and In Vivo and In Vitro Studies

Endoplasmic reticulum (ER) stress and oxidative stress contribute greatly to myocardial ischemia-reperfusion (MI/R) injury. Naringenin, a flavonoid derived from the citrus genus, exerts cardioprotective effects. However, the effects of naringenin on ER stress as well as oxidative stress under MI/R condition and the detailed mechanisms remain poorly defined. This study investigated the protective effect of naringenin on MI/R-injured heart with a focus on cyclic guanosine monophosphate- (cGMP-) dependent protein kinase (PKG) signaling. Sprague-Dawley rats were treated with naringenin (50 mg/kg/d) and subjected to MI/R surgery with or without KT5823 (2 mg/kg, a selective inhibitor of PKG) cotreatment. Cellular experiment was conducted on H9c2 cardiomyoblasts subjected to simulated ischemia-reperfusion treatment. Before the treatment, the cells were incubated with naringenin (80 μmol/L). PKGIα siRNA was employed to inhibit PKG signaling. Our in vivo and in vitro data showed that naringenin effectively improved heart function while it attenuated myocardial apoptosis and infarction. Furthermore, pretreatment with naringenin suppressed MI/R-induced oxidative stress as well as ER stress as evidenced by decreased superoxide generation, myocardial MDA level, gp91phox expression, and phosphorylation of PERK, IRE1α, and EIF2α as well as reduced ATF6 and CHOP. Importantly, naringenin significantly activated myocardial cGMP-PKGIα signaling while inhibition of PKG signaling with KT5823 (in vivo) or siRNA (in vitro) not only abolished these actions but also blunted naringenin's inhibitory effects against oxidative stress and ER stress. In summary, our study demonstrates that naringenin treatment protects against MI/R injury by reducing oxidative stress and ER stress via cGMP-PKGIα signaling. Its cardioprotective effect deserves further clinical study.

PL-011 Astaxanthin Reduces High Intensity Training Induced Myocardial Cell Apoptosis Via Activating Nrf2 in Rats

Objective Long-term intensive training may led to ischemia oxygen reaction and increase the ROS. Astaxanthin, as the super antioxidant, was investigated to against anti-oxidative stress. By supplementing the astaxanthin, we wanted to observe if it can mediated Nrf2 reduces myocardial cell oxidative injury in rats after high intensity training of 6 weeks. &#x0D; Methods 7-week SD male rats were divided into 3 groups randomly: control group ( C group，n =10)，high intensity training group ( HT group，n = 15)，astaxanthin and high intensity training group (HTA group，n = 15) . The rats in HTA group were given with astaxanthin 20 mg /kg·d and in HT group were given with oil during the training day．The serum cTnI，myocardial apoptosis index, the expression of myocardial BAX, Bcl2, Nrf2, HO-1, myocardial MDA，SOD and T- AOC activity were measured 24 hours after the last training．&#x0D; Results After 6-week tranning of high intensity, compared with group C, the serum cTNI, myocardial apoptosis index, the expression of BAX and myocardial MDA were significantly higher in group HT(P&lt;0.01).The Bcl2/Bax, the expression of HO-1, SOD and T-AOC activity were significantly declined (P&lt;0.01). After the intervention of 6-week astaxanthin, compared with group HT, the serum cTNI, myocardial MDA, the myocardial apoptosis index, the expression of BAX were significantly lower in HTA group (cTNI(ng/ml): 1.16±0.27 VS 2.47±0.39, P&lt;0.05; myocardial apoptosis index: 164.27±3.98 VS 196.20±9.65, P&lt;0.01; BAX: 58.40±5.95 VS 78.03±3.80, P&lt;0.01 ). Finally, Bcl2/Bax, SOD, T-AOC activity, the expression of Nrf2 and HO-1 were significantly higher (Bcl2/Bax : 1.92±0.10 VS 1.19±0.18, P&lt;0.01; SOD(U/mg): 52.38±6.15 VS 38.32±3.36, P&lt;0.01; T-AOC(U/mg): 30.22±4.07 VS 23.76±3.20, P&lt;0.01; Nrf2: 93.61±8.53 VS 74.26±6.69, P&lt;0.01; HO-1: 84.99±13.78 VS 64.22±11.39, P&lt;0.05). &#x0D; Conclusions The supplement of astaxanthin can mediate Nrf2 signaling pathway, and elevate the expression of Nrf2 and HO-1. Then it can increase the activity of SOD and T-AOC and reduce the myocardial oxidative level and myocardial apoptosis in rats caused by 6-week high intensity training. Finally, the structure and function of heart tissue are back to normal.

Effects of low dose of aliskiren on isoproterenol-induced acute myocardial infarction in rats.

This study examined the effects of aliskiren (Ali) (direct renin inhibitor) on serum cardiac enzymes (LDH and CK-MB), electrocardiography (ECG) changes, myocardial oxidative stress markers (MDA, CAT, and GSH) and the expression of Bcl2, HO-1, and Nrf2 genes in isoproterenol (ISO)-induced myocardial infarction (MI). A total of 40 male albino rats were allocated into four groups, (1) normal control (NC) group, (2) Ali group (rats received Ali at 10mg/kg/day p.o. for 5days), (3) ISO group (rats received ISO 150mg/kg i.p. for two consecutive days at 24h intervals), and (4) Ali + ISO group (rats received ISO + Ali at 10mg/kg/day p.o. for 5 days from the 2nd dose of ISO). ISO group showed significant rise in serum cardiac enzymes (CK-MB and LDH), myocardial damage scores, myocardial MDA, HO-1, myocardial Nrf2 expression with significant reduction in myocardial antioxidants (CAT and GSH), and Bcl2 expression compared to the normal group (p < 0.05). ECG showed ST segment elevation, prolonged QT interval and QRS complex, and increased heart rate in ISO group. Co-administration of Ali and ISO caused significant increase in cardiac enzymes and morphology with increase in MDA, serum K, and creatinine with significant decrease in Bcl2, HO-1, and Nrf2 without significant changes in ECG parameters compared to ISO group. We concluded that low dose of Ali seems to exacerbate the myocardial injury in ISO-MI, which might be due to the enhanced oxidative stress and apoptosis.

Antiapototic Effect of Tauroursodeoxycholic Acid Protects against Acute Doxorubicin Induced Cardiomyopathy in Rats

Background and purpose: Cardiotoxic carrdiomyopathy mediated by inflammation, oxidative stress lead to apoptosis with subsequently cell damage and heart failure. Tauroursodeoxycholic acid (TUDCA) is a bile acid that have anti-inflammatory and anti-oxidant effect, the current study aimed to examine the effect of administration of TUDCA on doxorubicin induced acute cardiomyopathy and explore the possible mechanism/s. Methods: Cardiomyopathy was induced in rats by single intraperitoneal (ip) injection of doxorubicin (DOX) (15 mg/kg). Results: doxorubicin administration exerted elevated levels of cereatine kinase-MB (CK-MB) and Lactate Dehydrogenase (LDH) in serum, in addition to myocardial TNF-α content, MDA levels, caspase-3, caspase-9 and caspase-12. However decrease in cardiac SOD and catalase content. Histopathological examination of myoendocardial section showed marked degeneration of cardiac muscle, distention of sarcoplasmic reticulum with marked accumulation of collagen fibers. Decrease immunoreactivity to antitroponin antibody. Echocardiography showed reduced LV fractional shortening, ejection fraction, and cardiac output. Treatment with TUDCA (250 mg/kg, ip) for 10 days significantly ameliorated histological changes and decreased the myocardium peroxidative damage in addition to decrease the cardiac markers for apoptosis. Conclusion: TUDCA can protect the heart from cardiotoxic effect of doxurubicin, The protective effects obtained by TUDCA is due to its inhibition of both endoplasmic stress and mitochondrial damage associated with chemotherapy treatment, with antioxidant and antiinflamatory properties. These results confirm the possible use of TUDCA to protect the heart during chemotherapy regimen.

Melatonin ameliorates myocardial ischemia/reperfusion injury in type 1 diabetic rats by preserving mitochondrial function: role of AMPK-PGC-1\u03b1-SIRT3 signaling

Enhancing mitochondrial biogenesis and reducing mitochondrial oxidative stress have emerged as crucial therapeutic strategies to ameliorate diabetic myocardial ischemia/reperfusion (MI/R) injury. Melatonin has been reported to be a safe and potent cardioprotective agent. However, its role on mitochondrial biogenesis or reactive oxygen species (ROS) production in type 1 diabetic myocardium and the underlying mechanisms remain unknown. We hypothesize that melatonin ameliorates MI/R injury in type 1 diabetic rats by preserving mitochondrial function via AMPK-PGC-1α-SIRT3 signaling pathway. Both our in vivo and in vitro data showed that melatonin reduced MI/R injury by improving cardiac function, enhancing mitochondrial SOD activity, ATP production and oxidative phosphorylation complex (II, III and IV), reducing myocardial apoptosis and mitochondrial MDA, H2O2 generation. Importantly, melatonin also activated AMPK-PGC-1α-SIRT3 signaling and increased SOD2, NRF1 and TFAM expressions. However, these effects were abolished by Compound C (a specific AMPK signaling blocker) administration. Additionally, our cellular experiment showed that SIRT3 siRNA inhibited the cytoprotective effect of melatonin without affecting p-AMPK/AMPK ratio and PGC-1α expression. Taken together, we concluded that melatonin preserves mitochondrial function by reducing mitochondrial oxidative stress and enhancing its biogenesis, thus ameliorating MI/R injury in type 1 diabetic state. AMPK-PGC1α-SIRT3 axis plays an essential role in this process.

Modulation of ECG, Myocardial Oxidative Stress Markers and Connexion 43 Expression by Ascorbic Acid and Ferulic Acid in Isoproterenol-Induced Myocardial Infarction in Rats

Objective: To assess the effects of ferulic acid (FeA) and ascorbic acid (AS) and combination of both on ECG variables, serum cardiac enzymes (AST, LDH, CK-MB), myocardial oxidative stress markers (MDA, SOD and GSH) and connexin 43 (Cx43) expressions in isoproterenol (ISO)-induced myocardial infarction. Methods: 40 male rats were equally allocated into 5 groups, 1) Control group, 2) ISO-induced MI group (rats received ISO 150 mg/Kg ip for 2 consecutive days at 24 h intervals), 3) FeA group (rats received ISO+FeA at 20 mg/kg/day po for 6 days), 4) AS group (rats received ISO+AS at 80 mg/kg/day po for 6 days) and 5) Combined group (rats received ISO+AS+FeA in the same previous doses). Results: The ISO group showed significant increase in serum cardiac enzymes (AST, CK-MB, and LDH), myocardial MDA and myocardial histopathological damage score with significant decrease in myocardial antioxidants (SOD and GSH) and Cx43expression compared to the control group (p<0.05). ECG traces of rats of ISO-induced MI, showed ST segment elevation, prolonged QT interval, shortened RR interval and increased heart rate. A combination of FeA and AS caused more significant improvement in the studied parameters than did each agent alone. ECG changes were improved significantly in the combined treatment group only. Conclusion: A combination of FeA and AS seems to offer a greater protective effect against ISO-induced myocardial infarction. This might be due to the synergism between their antioxidant properties as well as their effects on the density and location of Cx43 in myocardium.