Cardiac Function In Rats Research Articles

Moxibustion Improves Chronic Heart Failure by Inhibiting Autophagy and Inflammation via Upregulation of mTOR Expression.

How moxibustion improves chronic heart failure is extremely complex and still unclear. This study aimed to explore whether moxibustion inhibits autophagy and reduces inflammation by regulating mTOR expression to induce myocardial protective effects and alleviate symptoms associated with chronic heart failure. Echocardiography was used to detect cardiac function and cardiac structure of rats, including heart rate (HR), left atrium diameter (LA), left ventricular diameter (LV), left ventricular posterior wall (LVPW), interventricular septum (IVS), ejection fraction (EF), and fractional shortening (FS). BNP and NT-pro BNP levels were measured by enzyme-linked immunosorbent assay (ELISA). Autophagy-associated protein (ATG) genes and mTOR were detected by PCR. The expression of mTOR and phosphorylated-mTOR was detected through western blotting of proteins from myocardial tissue samples. The left ventricular inflammatory response was detected by immunohistochemistry and included ICAM-1, VCAM-1, MMP-2, and MMP-9 expression. The relationship between autophagy and inflammation was analyzed by correlation analysis. The results from echocardiography and ELISA showed that moxibustion could significantly improve heart function and structure. Western blot and PCR results showed that moxibustion treatment elevated mTOR expression. Further, moxibustion could inhibit autophagy and regulate the expression of key autophagy-related genes, including Vps34, ATG3, ATG5, ATG7, ATG12, and ATG13. By contrast, rapamycin could partially reduce the effects of moxibustion. Immunohistochemistry results indicated that moxibustion could reduce myocardial inflammation. Moreover, there was a positive correlation between autophagy and inflammation. Moxibustion can protect cardiac function in rats with heart failure, possibly inhibiting excessive autophagy of cardiomyocytes and reducing inflammatory reactions through the elevation of mTOR expression.

Aerobic exercise improves cardiac function in rats with chronic heart failure through inhibition of the long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1).

BackgroundTo explore the beneficial effects and underlying mechanisms of aerobic exercise on chronic heart failure (CHF).MethodsA CHF rat model was induced via left anterior descending coronary artery ligation. Four weeks post-surgery, CHF rats received aerobic exercise training over an 8-week period and cardiac function indexes including xxx were analyzed. To investigate the mechanisms involved in the aerobic exercise-induced benefits on CHF, overexpression of the long non-coding RNA MALAT1 was examined both in vivo and in vitro. Furthermore, the interaction between MALAT1 and the microRNA miR-150-5p and the downstream PI3K/Akt signaling pathway was investigated.ResultsCompared to the control group, the CHF rats showed evidence of left ventricular dysfunction including aggravated cardiac function indexes and lung to body weight ratio. The Masson staining demonstrated a significant degree of blue-stained fibrotic myocardial tissue in CHF rats compared to control rats. Furthermore, the levels of collagen I and collagen II were also markedly increased in CHF rats. Aerobic exercise improved cardiac function and left ventricular remodeling in rats with CHF. There was a significant reduction in the levels of the reactive oxygen species (ROS), inflammatory cytokines including TNF-α, IL-6, and IL-1β, and inflammatory mediums containing the matrix metalloproteinases (MMPs) MMP-2 and MMP-9. Moreover, CHF rats receiving aerobic exercise showed decreased myocardial apoptosis and increased expression of autophagy-related proteins including beclin-1 and LC3B-II. Overexpression of the lncRNA MALAT1 eliminated all the beneficial effects related to aerobic exercise in CHF rats. Subsequent investigations demonstrated that miR-150-5p expression was up-regulated in CHF-Tr rats and down-regulated in CHF-Tr-MALAT1 rats. Furthermore, the downstream PI3K/Akt signaling pathway was re-activated in CHF-Tr-MALAT1 rats. In vitro experiments revealed that overexpression of MALAT1 reduced the miR-150-5p levels, resulting in increased cellular apoptosis and less autophagy. In addition, overexpression of MALAT1 suppressed the downstream PI3K/Akt signaling pathway. Restoring miR-150-5p level with a miR-150-5p mimic decreased the cellular apoptosis and increased autophagy, and the downstream PI3K/Akt signaling pathway was re-activated.ConclusionsAerobic exercise improved cardiac function through inhibition of the lncRNA MALAT1 in CHF, and the potential mechanisms may be mediated via the miR-150-5p/PI3K/Akt signaling pathway.

Nicorandil inhibits cardiomyocyte apoptosis and improves cardiac function by suppressing the HtrA2/XIAP/PARP signaling after coronary microembolization in rats.

Cardiomyocyte apoptosis is a key factor in the deterioration of cardiac function after coronary microembolization (CME). Nicorandil (NIC) affects myocardial injury, which may be related to the inhibition of apoptosis. However, the specific mechanism of cardioprotection has not been elucidated. Therefore, we analyzed the impact of NIC on cardiac function in rats subjected to CME and its effect on the high‐temperature requirement peptidase 2/X‐linked inhibitor of apoptosis protein/poly ADP‐ribose polymerase (HtrA2/XIAP/PARP) pathway. Sprague Dawley rats were divided into four groups: Sham, CME, CME + NIC, and CME + UCF. Echocardiography was performed 9 hours after CME. Myocardial injury markers were evaluated in blood samples, and the heart tissue was collected for hematoxylin‐eosin staining, hematoxylin basic fuchsin picric acid staining staining, TdT‐mediated DUTP nick end labeling (TUNEL) staining, Western blot analysis of the HtrA2/XIAP/PARP pathway, and transmission electron microscopy. NIC ameliorated cardiac dysfunctioncaused by CME and reduced serum levels of CK‐MB and LDH. In addition, NIC decreased myocardial microinfarct size and apoptotic index. NIC reduced the Bax/Bcl‐2 ratio, levels of cleaved caspase 3/9, cytoplasmic HtrA2, and cleaved PARP, and increased the level of XIAP. The effects of NIC were similar to those of the HtrA2 inhibitor, UCF101. This study demonstrated that NIC reduces CME‐induced myocardial injury, reduces mitochondrial damage, and improves myocardial function. The reduction in cardiomyocyte apoptosis by NIC may be mediated by the HtrA2/XIAP/PARP signaling pathway.

Inhibition of microRNA-802-5p inhibits myocardial apoptosis after myocardial infarction via Sonic Hedgehog signaling pathway by targeting PTCH1.

The incidence of acute myocardial infarction (AMI) has increased significantly in recent years, seriously threatening human life and health. This paper focused on the role of microRNA-802-5p (miR-802-5p) in myocardial infarction (MI) and its underlying mechanisms. Quantitative Real-Time Polymerase Chain Reaction (RT-PCR) was employed to detect miR-802-5p expression. Western blot was performed to detect protein expression. Flow cytometry and terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining were performed to observe myocardial apoptosis. Hematoxylin-eosin (HE) staining was used to observe the morphology of myocardial tissue. The cardiac function of rats was detected using echocardiography. The expression of miR-802-5p was increased in hypoxic-treated H9c2 cells and infarcted myocardium in MI rats. Hypoxia treatment reduced the viability of cardiomyocytes and increased the level of lactate dehydrogenase (LDH) in the cell supernatant. Hypoxia treatment increased Bax expression in myocardial cells while Bcl-2 expression decreased, and the number of apoptotic cells increased. MiR-802-5p silencing reversed these effects. Moreover, miR-802-5p silencing reduced myocardial damage in MI rats, and significantly improved cardiac function. Through the Luciferase activity assay, we proved that miR-802-5p could directly target PTCH1. The knockdown of PTCH1 reversed the protective effect of miR-802-5p silencing on hypoxic myocardium. MiR-802-5p expression was increased in hypoxia-treated H9c2 cells and infarcted myocardium in MI rats. MiR-802-5p silencing could inhibit apoptosis after MI via activating Sonic Hedgehog signaling pathway by targeting PTCH1, thereby reducing myocardial injury and improving cardiac function of MI rats.

PEGylated Graphene Quantum Dot Improved Cardiac Function in Rats with Myocardial Infarction: Morphological, Oxidative Stress, and Toxicological Evidences.

Introduction The biocompatibility and potential application of graphene-based nanomaterials in biomedicine have been documented. The effects of polyethylene glycol-graphene quantum dots (GQDs-PEG) on cardiac function in rats with myocardial infarction (MI) were examined. Methods Wistar rats were randomly assigned to two main groups, each consisting of sham-Veh., MI-Veh., and MI+GQDs-PEG at doses of 5, 10, and 20 mg/kg. MI was induced by the closure of the left anterior descending (LAD) coronary artery. After MI, GQDs-PEG were injected at different doses IP every other day for two weeks. In the end, hemodynamic and heart contractility indices were assessed. The levels of myocardial MDA (malondialdehyde), SOD (superoxide dismutase), GPX (glutathione peroxidase), and TAC (total antioxidant capacity) were measured by the ELISA method. The serum ALP, ALT, AST, creatinine, and urea levels were measured using the photometric method. The infarct size was assessed by TTC staining. Results GQDs-PEG decreased the infarct size at doses of 10 and 20 mg/kg and recovered the MI-induced reductions of +dp/dt max and -dp/dt max in the study groups. GQDs-PEG normalized systolic blood pressure and left ventricular systolic pressure reduction at the dose of 20 mg/kg in the MI group. Heart SOD, GPX, and TAC increased in the GQDs-PEG 10 and 20 groups. Almost no signs of toxic effects due to GQDs-PEG administration were observed on the liver and kidneys. Conclusions The results provided clear evidence that GQDs-PEG improve cardiac performance and hemodynamic parameters in rats with MI by reducing oxidative stress. GQDs-PEG is proposed as a therapeutic target for the treatment of MI.

Upregulation of miR-335 reduces myocardial injury following myocardial infarction via targeting MAP3K2.

Acute myocardial infarction (AMI) is a serious cardiovascular disease with a high incidence worldwide and the main cause of sudden cardiac death. The aim of this article was to study the protective role of miR-335 in myocardial infarction (MI) and the underlying molecular mechanism. Thirty Sprague Dawley (SD) rats were randomly divided into sham group, MI + NC group and MI + agomiR-335 group. The expression of miR-335 in rat myocardium was detected by quantitative Real Time-Polymerase Chain Reaction (RT-PCR). Western blot was performed to detect the expression of TNF-α, IL-6, IL-1β, Caspase-3, Cleaved Caspase-3 (C-Caspase-3) and MAP3K2 in rat myocardium. On the 7th day of the establishment of the rat MI model, a high-resolution small animal ultrasound system was utilized to detect the cardiac function of the rats, and the heart tissues and blood samples of the rats were collected. The corresponding kits were purchased to detect the contents of LDH, CK-MB, MDA and SOD in rat serum, and HE staining was employed to observe the morphology of rat myocardial tissue. The expression of miR-335 in myocardial infarcted zones and border zones of MI rats decreased significantly. The upregulation of miR-335 remarkably inhibited myocardial inflammation and apoptosis after MI, thus improving the cardiac function of MI rats. Compared with the sham group, the MAP3K2 expression in the MI + NC group was observably increased, while the overexpression of miR-335 could inhibit the expression of this protein. Through the Luciferase reporter gene experiment, we found that miR-335 could directly target MAP3K2. The expression of miR-335 decreased in myocardial tissue after MI, and the overexpression of miR-335 reduced myocardial damage by inhibiting oxidative stress, inflammation, and apoptosis via targeting MAP3K2, thereby improving the cardiac function of MI rats.

Resveratrol Inhibits Myocardial Apoptosis by Regulating the Protein Kinase R-like Endoplasmic Reticulum Kinase Endoplasmic Reticulum Stress Pathway and Improves Myocardial Remodeling and Cardiac Function after Myocardial Infarction

To analyze the effect of resveratrol on myocardial remodeling and cardiac function after myocardial infarction by inhibiting myocardial cell apoptosis through regulating silent information regulator 1/protein kinase R-like endoplasmic reticulum kinase pathway. 32 healthy male sprague dawley rats were divided into control group (without any treatment), model group (ligation of left anterior descending branch to establish a model), sham operation group (ligation of left anterior descending branch without ligation) and resveratrol group (ligation of left anterior descending branch+resveratrol 8 mg/kg/d), 8 rats each. The changes of cardiac function, myocardial remodeling, myocardial apoptosis and silent information regulator 1/protein kinase R-like endoplasmic reticulum kinase pathway related proteins were observed 4 w after modeling. Left ventricular end-diastolic diameter and left ventricular end-systolic dimension levels in the model group were significantly higher than those in the control group, left ventricular ejection fraction and left ventricular short axis shortening rate levels were significantly lower than those in the control group (p<0.01), left ventricular end-diastolic diameter and left ventricular end-systolic dimension levels in the resveratrol group were significantly lower than those in the model group and left ventricular ejection fraction and left ventricular short axis shortening rate levels were significantly higher than those in the model group (p<0.01). In the model group, the myocardial cells were arranged in a disordered manner and fibrogenic hyperplasia occurred, while the pathological changes of the myocardial cells in the resveratrol group were reduced compared with the model group. The collagen volume fraction of myocardial tissue in the model group was significantly higher than that in the control group (p<0.05) and the collagen volume fraction in the resveratrol group was significantly lower than that in the model group (p<0.05). The apoptosis rate of myocardial cells in the model group was significantly higher than that in the control group (p<0.01) and the apoptosis rate of myocardial cells in the resveratrol group was significantly lower than that in the model group (p<0.01). The expression levels of Phosphate-protein kinase R like endoplasmic reticulum kinase, Phosphate eukaryotic initiation factor 2 and Activating transcription factor 4 in the model group were significantly higher than those of the control group and the expression levels of Silent Information Regulator 1 were significantly lower than those of the control group (p<0.01). The expression levels of Phosphate-protein kinase R like endoplasmic reticulum kinase, Phosphate eukaryotic initiation factor 2 and Activating transcription factor 4 in the resveratrol group were significantly lower than those of the model group and the expression levels of silent information regulator 1 were significantly higher than those of the model group (p<0.01). Resveratrol can reduce apoptosis of myocardial cells after myocardial infarction by regulating the silent information regulator 1/protein kinase R-like endoplasmic reticulum kinase pathway endoplasmic reticulum stress pathway and improve myocardial remodeling and cardiac function in rats, providing a new target for clinical treatment of myocardial infarction.

Improvement of Cardiac Function in Rats With Myocardial Infarction by Low-Intensity to Moderate-Intensity Endurance Exercise Is Associated With Normalization of Klotho and SIRT1.

Exercise training (Ex) has beneficial effects on cardiovascular diseases by increasing Klotho and SIRT1. This study aimed to investigate whether the beneficial impact of Ex on myocardial infarction (MI) is mediated through Klotho and SIRT1. Fifty-six Wistar rats were divided into 4 main groups of Sham, MI, Ex, and MI + Ex. MI was induced by the closure of the left anterior descending. Animals were trained by endurance exercise for 4 weeks. In the end, hemodynamic and heart contractility indices were assessed. The levels of Klotho and SIRT1 in the serum and heart were measured by enzyme-linked immunosorbent assay and Western blot, respectively. The ADAM17 level in the heart and kidneys was assessed by enzyme-linked immunosorbent assay. The infarct size and fibrosis area were assessed by triphenyltetrazolium chloride and Masson trichrome staining, respectively. Ex recovered the reduction of dp/dt max and dp/dt min and decreased myocardial infarct size and fibrotic area in the MI group. Ex normalized the increase in heart rate, systolic blood pressure, left ventricular systolic pressure, and left ventricular end diastolic pressure in the MI group. Ex also normalized the reduction of the levels of Klotho and SIRT1 in serum and heart in the MI group. The changes of Klotho and SIRT1 in serum were positively correlated. Ex also restored ADAM17 levels in the MI group. Ex improved cardiac function in the MI group and is associated with reduction of the infarct size and normalization of Klotho and SIRT1 levels. Regarding unidirectional changes in Klotho and SIRT1, these proteins may play a role in beneficial effects of Ex on MI recovery.

斑点追踪技术评价健心颗粒对心衰大鼠左室功能的影响

斑点追踪技术评价健心颗粒对心衰大鼠左室功能的影响

Effects of different doses of levosimendan combined with Shenmai injection on immune function and galectin-3 and HSP70 levels in rats with acute heart failure

To investigate the effects of different doses of levosimendan combined with Shenmai injection on immune function and galectin-3 and heat shock protein 70 (HSP70) levels in rats with acute heart failure. Forty eight specific-pathogen free Sprague Dawley male rats were selected and divided into 6 groups according to different administration schemes after the heart failure model was established. The left ventricular end diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF) of rats in each group were observed before and after treatment. After treatment, rats in groups A–D and the model group (MG) showed decreased LVEDDs compared with the control group (CG), and group D showed the highest reduction. In contrast, rats in groups A–D and the MG showed increased LVEFs compared with the CG, and group D showed the highest increase. The MG and groups A–D rats showed an increased percent of CD3+ T cells and CD4+/CD8+ T cell ratio compared with the CG. Levosimendan combined with Shenmai injection optimized the maintenance of immune and cardiac function in rats with acute heart failure compared with Shenmai injection alone. The higher dose of levosimendan combined with Shenmai injection improved the inflammatory reaction and levels of galectin-3 and HSP70.

Dipeptidyl peptidase 4 inhibitors attenuate cardiac ischaemia-reperfusion injury in rats with diabetes mellitus type 2.

The aim of our study was to assess and compare the effects of dipeptidyl peptidase 4 (DPP4) inhibitors, saxagliptin and sitagliptin, on metabolic control of disease and cardiac function in rats with diabetes mellitus type 2 (T2DM). This research would provide novel understanding into the potentially protective effects of DPP4 inhibitors in helping salvage of the heart exposed to ischaemia-reperfusion (I-R) injury. Forty-eight Wistar albino rats were randomly divided into four groups: CTRL, Control healthy group; T2DM, rats with T2DM; T2DM+Sit, rats with T2DM treated with 0.6mg/kg of sitagliptin; T2DM+Sax, rats with T2DM treated with 0.45mg/kg of saxagliptin for 3weeks. At the end of the protocol, in vivo cardiac function was assessed by echocardiography, while in the blood samples glucose and insulin were determined. Additionally, ex vivo heart function was estimated on a model of I-R injury using Langendorff apparatus. Immunohistochemical analysis was used to determine the degree of myocardial apoptosis and necrosis, while DPP4 staining was performed to assess the cardiac DPP4 expression. Data were analyzed using a one-way analysis of variance (ANOVA) and the post hoc Bonferroni test for multiple comparisons. Improved glycoregulation was noticed in rats that received DPP4 inhibitors compared to untreated diabetic rats (P<.05). Moreover, better in vivo systolic function was observed in rats treated with both DPP4 inhibitors as evidenced by an increase in fractional shortening when compared to T2DM (P<.05). Most parameters of cardiac function in treated rats remained unaltered during reperfusion, thus suggesting that both drugs protected myocardium during flow restoration. Better effects on coronary circulation were achieved after sitagliptin application. Additionally, both DPP4 inhibitors showed similar potential to attenuate cardiac necrosis and apoptosis. Saxagliptin and sitagliptin might be efficient in preserving myocardial function and morphology in ex vivo induced I-R cardiac injury in rats with T2DM.

Exogenous Hydrogen Sulfide Alleviated Left Ventricular Fibrosis Via Enhancing Cardiac Autophagy and Decreasing Cardiomyocyte Apoptosis in StreptozotocinInduced Diabetic Rats: From Network Pharmacology to Experimental Pharmacology

Streptozotocin (STZ)-induced diabetes mellitus (DM) model shows the signal of cardiac dysfunction, which is manifested as myocardial fibrosis and hypertrophy. This study was designed to predict targets of sodium hydrosulfide (NaHS) for diabetic cardiomyopathy and its corresponding triggered pathways by network pharmacology analysis and test the effects of NaHS as well as its mechanism as possible modulators of left ventricular remodeling in diabetic rats. The drug-target networks were constructed via approaches of network pharmacology, and the predicted targets and pathways were validated by in vivo experiments. Rats were randomly divided into 3 groups (n=6/group): STZ-induced DM group (STZDM); STZ-induced DM treated with H2S group (STZ-NaHS); control group. The control group was treated with daily saline (i.p.); the diabetic model was induced by intraperitoneal (i.p.) injections of 40 mg/kg/day STZ. After 12 weeks, the rat cardiac function was determined, and the pathological morphology of the heart was analysed by Masson trichrome staining in each group. The expression level of matrix metalloproteinase 9 (AGEs), CSE, CBS and several autophagy associated proteins were detected by the ELISA analysis. Results from the PPI network implied that 27 targets were key regulators. The AGE-RAGE signaling pathway in diabetic complications and the apoptotic signaling pathway was discovered to be the key to anti-diabetic cardiomyopathy of NaHS upon the GO enrichment analyses and KEGG pathway. In the in vivo experiment, compared with the control group, cardiac fibrosis and attenuated left ventricular function were observed. Furthermore, compared with the control group, the expression level of CSE, CBS and autophagy associated proteins Atg5 was significantly decreased, while that of AGEs, autophagy associated proteins p62 and p-ERK1/2 was significantly increased in the STZDM group (P&lt;0.05). In the STZ-NaHS group, cardiac fibrosis and ventricular dysfunction were ameliorated, the expression level of CSE, CBS and autophagy associated proteins Atg5 was increased, and the expression level of AGEs, autophagy associated proteins p62 and p-ERK1/2 was significantly decreased (P&lt;0.05). In conclusion, H2S may alleviate cardiac fibrosis of the STZ-induced DM rat model by enhancing cardiac autophagy, inhibiting cardiomyocyte apoptosis and downregulating p-ERK1/2.

In vivo effects of nitrosyl hydrogen on cardiac function and sarcoplasmic reticulum calcium pump (SERCA2a) in rats with heart failure after myocardial infarction.

Abnormal Ca2+ circulation in cardiomyocytes is an important cause of decreased myocardial contractility in failing hearts. Nitroxyl hydrogen (HNO) can oxidize Ca2+ cycle-related proteins, alter their biological functions, promote Ca2+ recovery as well as release, and enhance myocardial contractility. In this study, we aim to observe the effect of nitrosyl hydrogen (HNO) on the cardiac function of rats with heart failure and elucidate the underlying mechanism. Twenty six male Wistar rats were randomly divided into heart failure group (HF group), Angeli's salt treatment group (HF + AS group) and sham operation group (Sham group). The HF + AS group rats were treated with HNO donor Angeli's salt by intraperitoneal injection of 1 mg/kg/d, and the rats in the HF group and the Sham group were given the same amount of normal saline. Cardiac function was measured by echocardiography before and after treatment. NT-proBNP was measured by enzyme immunoassay (ELISA) kit after treatment. Western blot were used to measure the expression of sarcoplasmic reticulum Ca2+-ATPase (SERCA) in protein levels in rats. The activities of SERCA2a were detected by the biochemical kit finally. We found that Nitrosyl hydrogen could significantly increase LVEF, +dp/dt, -dp/dt (P<0.05), significantly decrease NT-ProBNP and LVEDP (P<0.01), and significantly enhance the activities of SERCA2a protein (P<0.05). These findings suggest that Nitrosyl hydrogen could improve the cardiac function possibly by increasing protein activities of SERCA2a in rats.

Activation of the CaR-CSE/H2S pathway confers cardioprotection against ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury is a multifactorial process triggered when an organ is subjected to transiently reduced blood supply. The result is a cascade of pathological complications and organ damage due to the production of reactive oxygen species following reperfusion. The present study aims to evaluate the role of activated calcium-sensing receptor (CaR)-cystathionine γ-lyase (CSE)/hydrogen sulfide (H2S) pathway in I/R injury. Firstly, an I/R rat model with CSE knockout was constructed. Transthoracic echocardiography, TTC and HE staining were performed to determine the cardiac function of rats following I/R Injury, followed by TUNEL staining observation on apoptosis. Besides, with the attempt to better elucidate how CaR-CSE/H2S affects I/R, in-vitro culture of human coronary artery endothelial cells (HCAECs) was conducted with gadolinium chloride (GdCl3, a CaR agonist), H2O2, siRNA against CSE (siCSE), or W7 (a CaM inhibitor). The interaction between CSE and CaM was subsequently detected. Plasma oxidative stress indexes, H2S and CSE, and apoptosis-related proteins were all analyzed following cell apoptosis. We found that H2S elevation led to the improvement whereas CSE knockdown decreased cardiac function in rats with I/R injury. Moreover, oxidative stress injury in I/R rats with CSE knockout was aggravated, while the increased expression of H2S and CSE in the aortic tissues resulted in alleviated the oxidative stress injury. Moreover, increased H2S and CSE levels were found to inhibit cell apoptotic ability in the aortic tissues after I/R injury, thus attenuating oxidative stress injury, accompanied by inhibited expression of apoptosis-related proteins. In HCAECs following oxidative stress treatment, siCSE and CaM inhibitor were observed to reverse the protection of CaR agonist. Coimmunoprecipitation assay revealed the interaction between CSE and CaM. Taken together, all above-mentioned data provides evidence that activation of the CaR-CSE/H2S pathway may confer a potent protective effect in cardiac I/R injury.

Abstract 13764: Chronic Electronic Cigarette Vapor Exposure Leads to Impaired Cardiac Function in Experimental Rat Myocardial Ischemia/reperfusion Model

Background: We investigated the effects of long-term electronic cigarettes with nicotine (eC) vaping on cardiac function and structure in rats subjected to myocardial infarction (MI). Methods: After 8 weeks of exposure to either pure air (n=20) or eC (n=20), rats were anesthetized, and were subjected to 30 minutes of coronary artery occlusion followed by 3 hours of reperfusion. Cardiac function was assessed by echocardiogram and pressure measurements of the aorta and left ventricle (LV). Cardiac output (CO) was measured using a thermodilution catheter. At 3 hours of reperfusion, ischemic risk zone, no-reflow and infarct areas were determined. Results: Prior to coronary artery occlusion, chronic eC exposure was associated with a lower CO (45 ± 2 ml/min ) compared to air (55 ± 4 ml/min; p&lt;0.05)) and a decrease in +dP/dt (5226 ± 294 mmHg/s versus 6062 ± 271 mmHg/s; p=0.05). After 30 minutes of coronary occlusion and 2.5 hours of reperfusion, CO and LV + dp/dt fell in both groups, but remained significantly lower in eC compared to the pure air group (Table). LV systolic and diastolic dimensions were significantly smaller in the E-Cig group compared to the air group. Systolic and diastolic anterior LV wall thickness were significantly thicker in the eC group after reperfusion. The ischemic risk size was comparable between the 2 groups. MI size was 48.8 ± 4.8% of the ischemic risk zone in the air group and 45.4 ± 4.4 % in the eC group (p=0.603). The area of no reflow was 26.7 ± 4.0% of the ischemic risk zone in the air group and 21.1 ± 3.5% in the E-C group (p=0.298). Chronic eC exposure did not change heart rate and blood pressure, but the significantly increased the systemic arterial resistance. Conclusions: Chronic exposure to eC significantly impaired cardiac function in rats prior to and during ischemia/reperfusion, increased arterial resistance, but did not increase infarct size or no-reflow zone. Increased LV wall thickness of the risk zone suggested that eC may have increased edema.

Abstract 13040: Left Ventricle Dysfunction is Prevented by the Treatment With Methotrexate Carried in Lipid Nanoparticles in Lipopolysaccharide-injected Rats

Introduction: In infectious processes, left ventricle (LV) dysfunction is often associated with dysregulation of the immune response. LDE, a lipid core nanoparticle resembling LDL, is able to concentrate in inflammatory sites. We showed that methotrexate (MTX), associated with LDE, modulated inflammation and improved cardiac function in rats with myocardial infarction Hypothesis: Investigate therapeutic effects of LDE-MTX on LV function in lipopolysaccharide (LPS)-injected rats Methods: Wistar rats were submitted to 2 injections of LPS (10mg/kg ip), with 24h interval. Animals were allocated to control group (CT, without LPS) and 3 LPS groups: LDE, treated with only LDE; MTX, with commercial MTX; and LDE-MTX. LDE-MTX dose was 1mg/kg I.P. 72h after LPS, animals were submitted to echocardiographic analysis. Animals were euthanised for analysis of the LV Results: Rats treated with LDE developed diastolic dysfunction and presented decreased diastolic volume and diameter of the LV, which was prevented by LDE-MTX. Only LDE-MTX treatment elicited cardiac hypertrophy through the increase of the thickness of LV septum and posterior wall, LV mass, relative heart weight and myocyte diameter. Inflammatory and apoptotic markers were similar in LPS groups, but LDE-MTX treatment increased macrophage recruitment (CD68). Angiogenesis, represented by vascular endothelial growth factor (VEGF), was higher in LDE-MTX compared to all other groups. Hypoxia-inducible factor 1 alpha, which was remarkably higher in LDE, was normalized by LDE-MTX to CT levels. A1, A2b and A3 adenosine receptors expression was higher in LDE-MTX, compared to CT, indicating an increase in intracellular adenosine. Myocyte diameter was positively correlated with VEGF (r2= 0.52; p&lt;0.0001) Conclusions: The increased recruitment of immune cells to the LV indicates that treatment with LDE-MTX was effective in activating immune response, impaired by LPS. LDE-MTX increased intracellular adenosine availability, contributing to an adaptive LV hypertrophy, increase in angiogenesis and diminished cellular hypoxia. These mechanisms conceivably elicited the observed LV improvement of diastolic dysfunction caused by LPS challenge

Cellular channelopathy mediated by hypergravity: IL-6-mediated Nkcc1 activation and enhanced Trpm2 expression in rat atrium.

Although cardiac tissue is considered a target of gravitational force (g-force), the mechanism of hypergravity on the ion modulation or identification of ion transporters is still unknown. Thus, we determine the effect of hypergravity on a physical force-sensitive cytokine, IL-6 and its related channel activity to investigate rat cardiac function changes in response to accelerated g-force. Serum IL-6 levels and intracellular calcium levels of the right atrium were moderately increased under hypergravity stimulation (4g). IL-6 was involved in the modulation of sodium-potassium-chloride cotransporter (Nkcc) activity. Surprisingly, the right atrium under 4g revealed significantly enhanced Nkcc1 activity. The use of IL-6 on the NKCC1-overexpressed or native NKCC-expressing cells also showed enhanced NKCC1 activity. Hypergravity conditions were also involved in the oxidative stress activated Trpm2 channel and revealed an enhanced expression of the Trpm2 channel under 4g in the rat right atrium. In conclusion, hypergravity revealed that moderate increases in serum IL-6 and enhanced Nkcc1 activity was modulated by IL-6. In addition, enhanced Trpm2 channel expression could be involved in the increased intracellular calcium levels of the right atrium under hypergravitational force. We therefore address that enhanced physical force-sensitive cytokine and oxidative stress by the gravitational force mediate activation of the cotransporter involved in possibilities of edema and calcium loading in cardiac tissue.

Hyaluronate supports hESC-cardiomyocyte cell therapy for cardiac regeneration after acute myocardial infarction.

IntroductionEnormous progress has been made in cardiac regeneration using human embryonic stem cell‐derived cardiomyocyte (hESC‐CM) grafts in pre‐clinical trials. However, the rate of cell survival has remained very low due to anoikis after transplantation into the heart as single cells. Numerous solutions have been proposed to improve cell survival, and one of these strategies is to co‐transplant biocompatible materials or hydrogels with the hESC‐CMs.MethodsIn our study, we screened various combinations of biomaterials that could promote anoikis resistance and improve hESC‐CM survival upon co‐transplantation and promote cardiac functional recovery. We injected different combinations of Matrigel, alginate and hyaluronate with hESC‐CM suspensions into the myocardium of rat models with myocardial infarction (MI).ResultsOur results showed that the group treated with a combination of hyaluronate and hESC‐CMs had the lowest arrhythmia rates when stimulated with programmed electrical stimulation. While all three combinations of hydrogel‐hESC‐CM treatments improved rat cardiac function compared with the saline control group, the combination with hyaluronate most significantly reduced pathological changes from left ventricular remodelling and improved both left ventricular function and left ventricular ejection fraction by 28 days post‐infarction.ConclusionHence, we concluded that hyaluronate‐hESC‐CM is a superior combination therapy for promoting cardiac regeneration after myocardial infarction.

Effect of Yixinshu Capsules on calcium regulatory protein in cardiac myocytes of rats with heart failure

To explore the molecular mechanism of Yixinshu Capsules(YXS) in restoring cardiac function in rats with heart failure(HF) from the perspective of calmodulin in cardiac myocytes on the basis of determining the therapeutic effect of YXS on HF. The SD rats were subjected to the surgery of ligating the anterior descending branch of the left coronary artery for 4 weeks to established myocardial ischemia-induced heart failure animal model. Then the rats were randomly divided into Sham operation group(Sham, saline), model group(HF, saline), high dose YXS group(HF+YXS-H, 1 600 mg·kg~(-1)·d~(-1)), low dose YXS group(HF+YXS-L, 800 mg·kg~(-1)·d~(-1)) and positive drug valsartan group(HF+VST, 8 mg·kg~(-1)·d~(-1)). After continuous intragastric administration for 6 weeks, the rats were sacrificed and myocardial tissue was collected. Real time quantitative polymerase chain reaction(RT-PCR) and Western blot were used to detect the expression of genes and proteins related to calcium regulation in cardiomyocytes. RESULTS:: showed that as compared with the model group, YXS increased the transcription level of Atp2 a2, Ryr2, CACNA1 C and PRKACA, and increased the expression levels of P-Ryr2, CACNA1 C and SERCA2 a, while decreased the level of NCX1.On the other hand, YXS treatment significantly decreased the RIP3 level and the phosphorylation of its substrate CaMKⅡ protein, and enhanced the phosphorylation expression of PLB. In summary, YXS therapy could regulate the expression of genes and proteins related to calcium regulation in cardiomyocytes, decrease RIP3 and the phosphorylation of CaMKⅡ protein, increase the phosphorylation of PLB at Ser16, and increase the expression of SERCA2 a protein, suggesting that YXS may regulate myocardial calcium homeostasis through CaMKⅡ/PLB/SERCA2 a pathway, to improve the ability of calcium uptake in sarcoplasmic reticulum and stabilize intracellular free Ca~(2+), so as to improve the cardiac function in rats with heart failure. Our study revealed the possible mechanism of YXS in the treatment of heart failure, especially from the perspective of intervention of calmodulin, promoting the clinical application of YXS.

MicroRNA-338 in MSCs-derived exosomes inhibits cardiomyocyte apoptosis in myocardial infarction.

Myocardial infarction (MI) is caused by myocardial ischemia and hypoxia, which causes irreversible damage to the myocardium and seriously endangers human health. Exosomes are small, monolayer-structured extracellular vesicles that transport proteins, lipids, mRNAs, and miRNAs between cells. Mesenchymal stem cells (MSCs) can secrete a large number of exosomes and play a role in many pathophysiological processes. The purpose of this paper was to investigate the role of exosomal microRNA-338 (miR-338) in MI and its underlying mechanism of action. We transfected rat bone marrow-derived MSCs with miR-338 mimic or negative control and extracted exosomes secreted by MSCs. Expression of miR-338 in MSCs, exosomes, and H9c2 cells co-cultured with exosomes was detected by PCR. Then, we treated H9c2 cells with H2O2. We transfected miR-338 inhibitor into H9c2 cells co-cultured with exosomes to further study the function of miR-338. Apoptosis of H9c2 cells were observed by Western blot, flow cytometry, and cell staining. We also established a MI rat model to study the function in vivo and injected exosomes in the myocardium. Seven days later, we used echocardiography to detect the heart function of rats. MiR-338 was upregulated in MSCs transfected with miR-338 mimic, exosomes, and H9c2 cells co-cultured with exosomes. When H9c2 cells were co-cultured with exosomes overexpressing miR-338, the expression of Bax was decreased while the expression of Bcl-2 was increased, and the apoptosis rate was also decreased as shown in flow cytometry, and the amount of caspase3 fluorescence was also decreased. Cardiac function was markedly improved after intramyocardial injection of exosomes overexpressing miR-338 in rats. It was demonstrated using computational tools, Western blot, and Luciferase reporter gene experiments that miR-338 could regulate JNK pathway via targeting MAP3K2. Exosomal miR-338 can inhibit cardiomyocyte apoptosis and improve cardiac function in rats with myocardial infarction by regulating MAP3K2/JNK signaling pathway.