Myocardial Cell Apoptosis In Rats Research Articles

HTD4010 attenuates myocardial injury in mice with septic cardiomyopathy by promoting autophagy via the AMPK/mTOR signaling pathway

To investigate the protective effects of HTD4010 against lipopolysaccharide (LPS)-induced septic cardiomyopathy (SCM) in mice and explore the mechanisms mediating its effect. Forty-five male ICR mice were randomized equally into control group, LPS (10 mg/kg) group, and LPS+HTD4010 group (in which 2.5 mg/kg HTD4010 was injected subcutaneously at 1 h and 6 h after LPS injection). Cardiac function of the mice was evaluated by ultrasound, and pathological changes in the myocardial tissues were observed with HE staining. The levels of IL-6 and TNF-α in serum and myocardial tissues were detected using ELISA, and apoptosis of the cardiomyocytes was detected with TUNEL staining. The expression levels of the key proteins associated with apoptosis, autophagy and the AMPK/mTOR pathway in the myocardial tissues were detected using Western blotting. The ultrastructural changes of cardiac myocardial mitochondria was observed with transmission electron microscopy. LPS exposure caused severe myocardial damage in mice, characterized by myocardial fiber rupture, structural disorder, inflammatory cell infiltration, and mitochondrial damage. The LPS-treated mice exhibited significantly decreased cardiac LVEF and FS values, elevated IL-6 and TNF-αlevels in serum and myocardial tissue, and an increased myocardial cell apoptosis rate with enhanced expressions of Bax, p-62 and p-mTOR and lowered expressions of Bcl-2, LC3 II/I, Beclin-1 and p-AMPK (P < 0.05 or 0.01). Treatment of the septic mice with HTD4010 significantly alleviated myocardial damage, increased LVEF and FS values, reduced IL-6 and TNF-α levels in serum and myocardial tissue, decreased cardiomyocyte apoptosis, lowered myocardial expressions of Bax, p-62 and p-mTOR, and increased Bcl-2, LC3 II/I, Beclin-1 and p-AMPK expressions (P < 0.05 or 0.01). HTD4010 can attenuate myocardial injury in SCM mice possibly by promoting autophagy via modulating the AMPK/mTOR signaling pathway.

Effect and mechanism of Poria cocos polysaccharides on myocardial cell apoptosis in rats with myocardial ischemia-reperfusion injury by regulating Rho-ROCK signaling pathway

This study aimed to investigate the effect and underlying mechanism of Poria cocos polysaccharides(PCP) on myocardial cell apoptosis in the rat model of myocardial ischemia-reperfusion injury(MI/RI). Male SPF-grade SD rats were randomly divided into a sham group(saline), a model group(saline), low-and high-dose PCP groups(100 and 200 mg·kg~(-1)), and a fasudil group(10 mg·kg~(-1)), with 16 rats in each group. Except for the sham group, the other four groups underwent left anterior descending coronary artery ligation for 30 min followed by reperfusion for 2 h to establish the MI/RI model. The myocardial infarct area was assessed by TTC staining. Histological changes were observed through HE staining. Myocardial cell apoptosis was evaluated using TUNEL staining. Serum lactate dehydrogenase(LDH), creatine kinase MB(CK-MB), interleukin-1β(IL-1β) and IL-18 levels, myocardial superoxide dismutase(SOD) activity and malondialdehyde(MDA) levels were detected by ELISA. Protein expression of B-cell lymphoma 2(Bcl-2), Bcl-2 associated X protein(Bax), cleaved caspase-3, Ras homolog gene A(RhoA), myosin phosphatase target subunit 1(MYPT-1), phosphorylated MYPT-1(p-MYPT-1), and Rho-associated coiled-coil forming kinase 1(ROCK 1) were measured by Western blot. Pathological staining of myocardial tissue revealed that in the model group, there was focal necrosis of myocardial tissue, myocardial cell swelling, unclear boundaries, and neutrophil infiltration. These pathological changes were alleviated in the low-and high-dose PCP groups and the fasudil group. Compared with the model group, the low-and high-dose PCP groups and the fasudil group showed significantly reduced myocardial infarct area and myocardial cell apoptosis rate. Compared with the sham group, the model group exhibited elevated serum LDH, CK-MB, IL-1β and IL-18 levels, increased MDA levels, relative protein expression of Bax, cleaved caspase-3, RhoA, ROCK1 and p-MYPT-1, and decreased myocardial SOD levels and Bcl-2 protein expression. Compared with the model group, the PCP groups and the fasudil group showed lowered serum LDH, CK-MB, IL-1β and IL-18 levels, decreased MDA levels, relative protein expression of Bax, cleaved caspase-3, RhoA, ROCK1 and p-MYPT-1, and increased myocardial SOD levels and Bcl-2 protein expression. PCP exhibited a certain preventive effect on myocardial tissue pathological damage and myocardial cell apoptosis in MI/RI rats, possibly related to the inhibition of the Rho-ROCK signaling pathway activation, thereby reducing oxidative stress and inflammatory responses.

Protective effect of dexmedetomidine pre treatment against myocardial ischemia reperfusion injury in rats

Purpose: To determine the protective effect of dexmedetomidine pre-treatment against myocardial ischemia-reperfusion injury (MRI), and the involvement of ER stress and protein kinase R-like ER enzyme (PERK) signaling pathway in the process.&#x0D; Methods: Sixty male Sprague-Dawley (SD) rats were assigned to three groups: sham, model (ischemia-reperfusion), and dexmedetomidine pre-treatment groups. Myocardial infarction area was measured using 2,3,5-triphenyl tetrazolium chloride (TTC) method. Changes in heart structure were examined using H &amp; E, while myocardial cell apoptosis was determined with TUNEL assay. The protein expression levels of CHOP, glucose regulatory protein 78, ATF4, eukaryotic translation initiation factor 2-α (elf2-α), and PERK were assayed with Western blotting.&#x0D; Results: RPP, myocardial infarction area, myocardial cell apoptosis rate, and the expression levels of CHOP, GRP78, ATF4, elf2-α, and PERK were significantly raised, relative to sham. The structure of myocardial cells in sham-operated rats was intact and orderly. In contrast, the arrangement of myocardial cells in the model group was disordered, and the myofibrils were broken or wavy. However, the arrangement of myocardial cells in the dexmedetomidine group was significantly improved, when compared with the model group.&#x0D; Conclusion: Pretreatment with dexmedetomidine may exert a protective effect against MRI through suppression of ER stress and PERK signaling pathway. Further preclinical studies would be required to validate these findings.

Integrating UPLC-Q-Exactive Orbitrap/MS, network pharmacology and experimental validation to reveal the potential mechanism of Tibetan medicine Rhodiola granules in improving myocardial ischemia-reperfusion injury

Ethnopharmacology relevanceRhodiola granules (RG) is a traditional Tibetan medicine prescription that can be used to improve the symptoms of ischemia and hypoxia in cardiovascular and cerebrovascular diseases. However, there is no report on its use to improve myocardial ischemia/reperfusion (I/R) injury, and its potential active ingredients and mechanism against myocardial ischemia/reperfusion (I/R) injury remain unclear. Aim of the studyThis study aimed to reveal the potential bioactive components and underlying pharmacological mechanisms of RG in improving myocardial I/R injury through a comprehensive strategy. Materials and methodsUPLC-Q-Exactive Orbitrap/MS technology was used to analyze the chemical components of RG, the potential bioactive components and targets were tracked and predicted by the SwissADME and SwissTargetPrediction databases, and the core targets were predicted through the PPI network, as well the functions and pathways were determined by GO and KEGG analysis. In addition, the molecular docking and ligation of the anterior descending coronary artery-induced rat I/R models were experimentally validated. ResultsA total of 37 ingredients were detected from RG, including nine flavones, ten flavonoid glycosides, one glycoside, eight organic acids, four amides, two nucleosides, one amino acid, and two other components. Among them, 15 chemical components, such as salidroside, morin, diosmetin, and gallic acid were identified as key active compounds. Ten core targets, including AKT1, VEGF, PTGS2, and STAT3, were discovered through the analysis of the PPI network constructed from 124 common potential targets. These possible targets were involved in the regulation of oxidative stress and HIF-1/VEGF/PI3K-Akt signaling pathways. Furthermore, molecular docking confirmed that the potential bioactive compounds in RG have good potential binding abilities to AKT1, VEGFA, PTGS2, STAT3, and HIF-1α proteins. Then, the animal experiments showed that RG could significantly improve the cardiac function of I/R rats, reduce the size of myocardial infarction, improve the myocardial structure, and reduce the degree of myocardial fibrosis, inflammatory cell infiltration, and myocardial cell apoptosis rate in I/R rats. In addition, we also found that RG could decrease the concentration of AGE, Ox-LDL, MDA, MPO, XOD, SDH, Ca2+, and ROS, and increase the concentration of Trx, TrxR1, SOD, T-AOC, NO, ATP, Na+k+-ATPase, Ca2+-ATPase, and CCO. Moreover, RG could significantly down-regulate the expressions of Bax, Cleaved-caspase3, HIF-1α, and PTGS2, as well up-regulate the expressions of Bcl-2, VEGFA, p-AKT1, and p-STAT3. ConclusionIn summary, we revealed for the first time the potential active ingredients and mechanisms of RG for myocardial I/R injury therapy through a comprehensive research strategy. RG may synergistically improve myocardial I/R injury through anti-inflammatory, regulating energy metabolism, and oxidative stress, improving I/R-induced myocardial apoptosis, which may be related to the HIF-1/VEGF/PI3K-Akt signaling pathway. Our study provides new insights into the clinical application of RG and also provides a reference for the development and mechanism research of other Tibetan medicine compound preparations.

Expression of miR-320 and miR-204 in myocardial infarction and correlation with prognosis and degree of heart failure.

Myocardial infarction is a very dangerous cardiovascular disease with a high mortality rate under the modern developed medical technology. miRNA is a small molecule regulatory RNA discovered in recent years, which can play an important role in many cancers and other diseases. Medical data, machine learning and medical care strategies supporting the Internet of Things (IoMT) have certain applications in the treatment of myocardial infarction. However, the specific pathogenesis of myocardial infarction is still unclear. Therefore, this paper aimed to explore the expression of microRNA-320 and microRNA-204 in myocardial infarction and used the expression of microRNA-320 and microRNA-204 to predict the prognosis of patients with myocardial infarction. In order to discuss the expression of microRNA-320 and microRNA-204 in myocardial infarction in more detail. In this paper, 40 patients in the trial period were selected for clinical research, and 10 patients with normal cardiac function were selected in NHF group as control group. 10 patients with heart failure were selected as AMHF group. 10 patients with acute myocardial infarction were selected as AMNHF group. 10 patients with heart failure after old myocardial infarction were selected as OMHF group. AMHF group, AMNHF group and OMHF group were taken as the case group. This paper analyzed the difference of miR between different groups and determined that there were significant differences in the expression of miR-320 and miR-204 between different groups. Finally, the expression and prognosis of miR-320 and miR-204 in myocardial infarction were analyzed. The analysis results showed that the expression of microRNA-320 and microRNA-204 can inhibit the activity of myocardial cells. On the fifth day, the corresponding expression of microRNA-320 and microRNA-204 reduced the optical density of myocardial cells to 1.75 and 1.76, which was significantly lower than that on the first day. Moreover, excessive miR-320 expression and excessive miR-204 expression can increase the apoptosis rate of myocardial cells. The above results indicated that the high expression of microRNA-320 and microRNA-204 can be a bad prognostic factor in patients with myocardial infarction, showing that medical data, machine learning and medical care strategies supporting IoMT can play a role in the treatment of myocardial infarction. Therefore, it is urgent to understand the pathogenesis of heart failure after myocardial infarction and find new treatment schemes to improve the positive prognosis.

Effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/β-catenin/PPARγ pathway in arrhythmic rats

This paper aimed to investigate the effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/β-catenin/peroxisome proliferator-activated receptor γ(PPARγ) pathway in arrhythmic rats. SD rats were randomly divided into a control group, a model group, a low-dose(20 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a medium-dose(40 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a high-dose(80 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a propranolol hydrochloride(2 mg·kg~(-1)) group, with 12 rats in each group. Except the control group, rats in other groups were prepared as models of arrhythmia by sublingual injection of 1 mL·kg~(-1) of 0.002% aconitine. After grouping and intervention with drugs, the arrhythmia, myocardial cells apoptosis, myocardial tissue glutathione peroxidase(GSH-Px), catalase(CAT), malondialdehyde(MDA), serum interleukin-6(IL-6), prostaglandin E2(PGE2) levels, myocardial tissue apoptosis, and Wnt/β-catenin/PPARγ pathway-related protein expression of rats in each group were measured. As compared with the control group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA levels in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and β-catenin protein expression levels increased significantly in the model group, whereas the GSH-Px and CAT levels, and Bcl-2 and PPARγ protein expression levels in myocardial tissues reduced significantly. As compared with the model group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA leve in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and β-catenin protein expression levels reduced in the drug intervention groups, whereas the GSH-Px and CAT levels and Bcl-2 and PPARγ protein expression levels in myocardial tissues increased. The groups of total flavonoids of buckwheat flower and leaf were in a dose-dependent manner. There was no significant difference in the levels of each index in rats between the propranolol hydrochloride group and the high-dose group of total flavonoids of buckwheat flower and leaf. The total flavonoids of buckwheat flower and leaf inhibit the activation of Wnt/β-catenin pathway, up-regulate the expression of PPARγ, reduce oxidative stress and inflammatory damage in myocardial tissues of arrhythmic rats, reduce myocardial cell apoptosis, and improve the symptoms of arrhythmia in rats.

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 &lt;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 &lt;0.05). Compared with BMSCs group, the apoptosis rate of myocardial cells was decreased, and the levels of bFGF and FSTL1 were increased (P &lt; 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.

Quercetin Inhibits Pyroptosis in Diabetic Cardiomyopathy through the Nrf2 Pathway.

The present study investigated whether quercetin promotes the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) to inhibit pyroptosis progression and ameliorate diabetic cardiomyopathy. We evaluated the protective effects of quercetin against diabetic cardiomyopathy by analyzing the expression of pyroptosis pathway proteins, myocardial cell apoptosis rate, degree of myocardial fibrosis, and serum inflammatory indices in the hearts of model rats with diabetes. We evaluated the expression of Nrf2 in the nucleus of cardiomyocytes and H9C2 cells to clarify the role of quercetin in promoting the nuclear translocation of Nrf2. In addition, we coincubated cardiomyocytes with the Nrf2 inhibitor ML385 to confirm that quercetin inhibits the diabetes-induced cardiomyocyte pyroptosis via the Nrf2 pathway. We found that quercetin promoted the nuclear translocation of Nrf2 in cardiac cells of diabetic rats, increased the expression of the antioxidant proteins HO-1, GCLC, and SOD, reduced the accumulation of ROS and the degree of cardiomyocyte apoptosis, and alleviated diabetes-induced cardiac fibrosis. The therapeutic effects of quercetin were further validated in H9C2 cardiomyocytes. Interestingly, ML385 prevented the beneficial effects of quercetin on diabetic cardiomyopathy, further indicating that the quercetin-mediated inhibition of pyroptosis requires the participation of the Nrf2 pathway. In conclusion, quercetin promoted the nuclear translocation of Nrf2, increased the expression of antioxidant factors in cells, and inhibited the progression of cell pyroptosis, thereby alleviating diabetic cardiomyopathy.

MiR-1 mediated AMPK pathway on cardiomyocyte apoptosis in hypertensive rats

In recent years, it has been found that miRNA has a very close relationship with cardiovascular system diseases. Heart disease is accompanied by a change of the miRNA expression spectrum. Changing the expression of miRNA in or out of cells can cause heart diseases such as myocardial infarction, hypertrophy or arrhythmia. Mitogen-activated protein kinases (MAPKs) are important transmitters of cell surface signals to the nucleus. The family influences the biological responses of cells (e.g., proliferation, differentiation, transformation and apoptosis) by affecting the transcription and regulation of genes in animal cells. Based on the above background, the purpose of this study was to study the effect of the mir-1-mediated AMPK pathway on cardiomyocyte apoptosis in hypertensive rats. The expression level of miRNA-1 in cultured rat H9c2 cardiomyocytes was detected by real-time PCR to determine the success of the transfection. MTT method was used to detect the cell viability. Flow cytometry was used to detect the cell apoptosis, and real-time PCR and Western blot were used to detect the mRNA and protein expression of bcl-2. The results were compared with those of H9c2 cells (blank control group) and miRNA negative control fragments (negative control group). As an important kinase regulating energy homeostasis, AMPK is one of the central regulators of metabolism in eukaryotic cells and organisms, responsible for regulating cellular capacity input and output and maintaining the smooth functioning of cellular physiological activities. At the same time, AMPK is a key protein involved in a variety of signaling pathways. The results showed that the apoptosis rate of myocardial cells in the miRNA-1 group decreased (0.710 ± 0.009661)% vs (1.066667 ± 0.02603)% compared with that in the spontaneous hypertension control group (P < 0.001). The transfected miRNA-1mimics can up-regulate the expression of miRNA-1 in cells, inhibit the proliferation of cardiomyocytes and promote apoptosis.

Protective effect of ivabradine on mice with viral myocarditis and its mechanism

Viral myocarditis (VMC) is a type of cardiovascular disease caused by viral infection of myocardial cells characterized by myocardial interstitital inflammatory cell infiltration, myocardial fiber necrosis or figrinolysis. Ivabradine (IVA) is a commonly known drug used to control heart rate, resist inflammation and oxidative stress, particularly in VMC. Here, we have tried to evaluate the protective effects of IVA on mice with VMC and understand the possible mechanism behind this process. In order to complete the study, eighty male mice aged 6 weeks old were randomly divided into normal control, VMC model, low-dose IVA (L-IVA) and high-dose IVA (H-IVA) groups. Half an hour after modeling, IVA aqueous solution was administered intragastrically into L-IVA and H-IVA groups at 5 mg·kg-1·d-1 and 20 mg·kg-1·d-1, respectively for 14 consecutive days. Another 120 mice of the same batch were grouped and treated as described above. At 7 and 14 d, 6 mice in each group were sacrificed to obtain blood and heart samples. Body weight/heart weight (BW/HW) was calculated, hematoxylin-eosin staining was performed to observe the pathological changes of myocardium, and the level of cardiac troponin I (cTnI) was measured by ELISA. Related kits were employed to measure superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH-Px) and catalase (CAT) activites in myocardial homogenate, and the levels of interleukin-6 (IL-6), IL-18, IL-1β and tumor necrosis factor-α (TNF-α) were determined by double-antibody sandwich ELISA. TUNEL assay was performed to detect the apoptosis of myocardial cells. The protein expressions of Bcl-2, Bax and Caspase-3 in myocardial cells were measured by Western blotting. Compared to the VMC model group, the heart/body weight ratio, myocardial pathological score, cTnI level, MDA activity, and levels of IL-6, IL-18, IL-1β and TNF-α were found decreased, while survival rate and activity of SOD, GSH-Px and CAT increased in L-IVA and H-IVA groups (P &lt;0.05). The apoptosis rate of myocardial cells declined in L-IVA and H-IVA groups (P &lt;0.05), especially in H-IVA group. IVA downregulated the protein expressions of Bax and Caspase-3 and upregulated that of Bcl-2 (P &lt;0.05). Thus, it has been found that IVA elevates the survival rate of VMC mice and relieves myocardial damage possibly by enhancing antioxidant capacity and modulating apoptosis-related proteins to suppress apoptosis.

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.

Effects of Sevoflurane on Apoptosis of Myocardial Cells in IRI Rats.

Background Cardiomyocyte apoptosis functions essentially in ischemia/reperfusion- (I/R-) induced myocardial injury. It is suggested that autophagy is widely implicated in the regulation of cell survival and death. Sevoflurane, as a largely used inhalational general anesthetic, has been shown to have a protective effect on cardiomyocytes. However, it was yet elusive on the underlying mechanisms. Aim The objective of this study is to investigate the association of sevoflurane-mediated cardioprotective effects with autophagy regulation. Methods An in vitro hypoxia model was established in primary cardiomyocytes from fresh myocardial tissue of the rats. The apoptosis rate of myocardial cells treated with hypoxia and treated with sevoflurane was measured. Western blot and immunocytochemical assay were used to measure the protein expression. The cell proliferation rate and cell apoptosis were measured using the MTT assay and flow cytometry, respectively. Results The expression of apoptotic proteins including B cell lymphoma-2 (Bcl-2), CCAAT/enhancer-binding protein homologous protein (CHOP), glucose-regulated protein 78 (GRP78), and Bcl-2-associated X protein (BAX) in myocardium treated with sevoflurane was significantly lower than that in myocardium treated with hypoxia. The expression of adhesion proteins such as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in myocardium treated with sevoflurane was higher than that in myocardium treated with hypoxia, suggesting better connectivity of the myocardium. Conclusion Sevoflurane treatment reduced the apoptosis of myocardial cells after hypoxia treatment.

Protective role of emodin in rats with post-myocardial infarction heart failure and influence on extracellular signal-regulated kinase pathway

ABSTRACT We aimed to explore the effects of emodin on the energy metabolism of myocardial cells in rats with post-myocardial infarction (MI) heart failure (HF) and the extracellular signal-regulated kinase (ERK) pathway. The model of MI was established by ligation of the left anterior descending branch. After 4 weeks, the rats with left ventricular ejection fraction (LVEF) of ≤45% were used aspost-MI HF model animals and randomly divided into model, low-dose, middle-dose, high-dose and control groups (n=10). Low-, middle- and high-dose groups were gavaged with 20 mg/kg, 40 mg/kg and 60 mg/kg emodin daily, respectively. After administration for 14 d, the changes in LVEF, left ventricular end-systolic diameter (LVESD), left ventricular end-diastolic diameter (LVEDD) and interventricular septum thickness (IVS) were analyzed. The apoptosis rate of myocardial cells was detected by TUNEL staining. The levels of serum cardiac troponin I (cTnI) and peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1) were determined using ELISA, and the expressions of mitochondrial respiratory chain complex I protein and phosphorylated-ERK (p-ERK) in myocardial tissues were determined by Western blotting. Compared with model group, LVEDD, LVESD, apoptosis rate of myocardial cells, levels of serum cTnI and PGC-1, and expressions of complex I and p-ERK in myocardial tissues significantly decreased, while LVEF and IVS increased in low-dose, middle-dose, high-dose and control groups (P<0.05). The changes in the above indices were significantly dependent on the dose of emodin (P<0.05).Emodin can significantly relieve post-MI HF, reduce the apoptosis rate of myocardial tissues, and ameliorate the cardiac function of rats.

Effect of PD-1 Inhibitor on Cardiac Inflammatory Microenvironment and Radiation Induced Heart Injury

Effect of PD-1 Inhibitor on Cardiac Inflammatory Microenvironment and Radiation Induced Heart Injury

Beneficial effects and related mechanism of hawthorn leaves flavonoids on cardiac function in rats with acute myocardial infarction

Objective: To explore the effect and related regulatory mechanism of hawthorn leaf flavonoids (FHL) on cardiac function in rats with acute myocardial infarction (AMI). Methods: Sixty SPF male Sprague-Dawley rats (9-week-old, weighing 300-350 g) were used in this study. Ten rats were assigned to sham operation group, and the remaining 50 rats were used to establish the AMI model with coronary artery ligation method, AMI was successfully established in 36 rats. AMI rats were randomly divided into AMI group and FHL low-, medium-, and high-dose groups (n=9 for each group). Rats received intraperitoneal injection (10 ml·kg-1·day-1) with physiological saline and FHL solution with concentrations of 0.3, 0.6, and 1.2 mg/ml, respectively for 4 consecutive weeks. Echocardiography was performed at the end of experiments. Left ventricular end diastolic diameter (LVEDD), left ventricular end diastolic anterior wall thickness (LAWD), left ventricular ejection fraction (LVEF) and left ventricular end diastolic pressure (LVEDP) were measured. Then the rats were sacrificed under deep anesthesia, and the left ventricular anterior wall tissue was used for pathological examinations by hematoxylin-eosin (HE) staining. Other myocardial tissue was used for in situ terminal transferase labeling (TUNEL) staining, and the apoptosis rate of cardiomyocytes was calculated. The myocardial cell apoptosis rate, the mRNA, and protein expressions of phosphatidylinositol 3β-kinase (PI3K), protein kinase B (Akt), glycogen synthetase kinase-3 (GSK3β), cyclin D1 and the protein expressions of p-Akt and p-GSK3β were detected by real-time fluorescent quantitative PCR (RT-qPCR) and Western blot respectively. Results: Compared with sham operation group, the LVEDD and LVEDP of the rats in AMI group and FHL low-, medium-and high-dose groups were increased, and the LAWD and LVEF were reduced (all P<0.05). Compared with AMI group, LVEDD and LVEDP were reduced, and LAWD and LVEF were increased in FHL low-, medium-and high-dose groups (all P<0.05). LVEDD and LVEDP decreased, and LAWD and LVEF increased in proportion to the increase of FHL dose (all P<0.05). LVEDD and LAWD values were similar between FHL low-dose and medium-dose groups (both P>0.05). HE staining results evidenced necrotic myocardial tissue, together with disordered arrangement of myocardial fibers, and a large number of inflammatory cells infiltrated in the myocardial tissue in AMI group. The myocardial damage of rats in FHL low-, medium-, and high-dose groups was less than that of AMI group. The myocardial fibers were arranged neatly, but there were still partial breaks and a small amount of inflammatory cell infiltration in the myocardial tissue and there were scattered islands of normal myocardial tissue in the infarct area of these groups. Among them, myocardial damage was the least in FHL high-dose group. The results of TUNEL staining showed that compared with AMI group, the apoptosis rate of myocardial cells was significantly reduced in FHL low-, medium-, and high-dose groups (all P<0.001), but was still higher than that in sham operation group (all P<0.001). Myocardial cell apoptosis rate decreased in proportion with increasing FHL dose (P<0.05). The RT-qPCR results showed that compared with AMI group, the expression levels of PI3K and cyclin D1 mRNA were significantly upregulated in the myocardial tissue of rats in FHL low-, medium-, and high-dose groups, but still lower than those in sham operation group (all P<0.05), and PI3K and cyclin D1 mRNA expression levels increased with the increase dose of FHL (P<0.05). Western blot results showed that compared with AMI group, the expression levels of PI3K, p-Akt, p-GSK3β, and cyclin D1 were significantly upregulated in the myocardial tissue of rats in FHL low-, medium-, and high-dose groups, but still lower than those in sham operation group (all P<0.05), and the protein expression levels of PI3K, p-Akt, p-GSK3β, and cyclin D1 increased in proportion with the increase dose of FHL (all P<0.05). Conclusion: FHL can effectively improve cardiac function in rats with AMI, and the beneficial effects may be partly mediated through activating PI3K/GSK3β/cyclin D1 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.

Anti-apoptotic Effect of MiR-223-3p Suppressing PIK3C2A in Cardiomyocytes from Myocardial Infarction Rat Through Regulating PI3K/Akt Signaling Pathway.

We aimed to explore the regulatory mechanism of the axis of miR-223-3p-PIK3C2A-PI3K/Akt on cardiomyocyte apoptosis in rats with myocardial infarction. Thirty 8-week-old healthy male SD rats were used for establishing the sham group and the model group, with HE staining, TUNEL staining, and TTC staining performed. After the identification of the targeting relationship between PIK3C2A and miR-223-3p, experimental rats were randomly divided into seven groups by plasmid transfection, including the Blank group, negative control (NC) group, miR-223-3p mimic group, miR-223-3p inhibitor group, siRNA-PIK3C2A group, oe-PIK3C2A group, and miR-223-3p inhibitor + oe-PIK3C2A group. Four weeks after transfection, the expression levels of miR-223-3p and PIK3C2A in tissues as well as PI3K, Akt, Bax, and bcl-2 mRNA in cells were detected by qRT-PCR and western blot, in combination with the detection of apoptosis rate by flow cytometry. Compared with the sham group, the model group showed typical myocardial injury and abnormal staining, higher apoptotic index, and larger myocardial infarction area (all P < 0.05). PIK3C2A was the target gene of miR-223-3p. The expression level of miR-223-3p in model group was significantly lower than that in sham group, while the mRNA and protein expression levels of PIK3C2A increased significantly (all P < 0.05). In cell tests, the expression level of miR-223-3p increased significantly in miR-223-3p mimic group (P < 0.05), which, however, showed no significant change in siRNA-PIK3C2A group (P > 0.05). MiR-223-3p inhibitor group and siRNA-PIK3C2A group had obviously increased PI3K, Akt, mTOR and Bcl-2 mRNA, and protein expression, while decreased mRNA and protein expression of PIK3C2A and Bax (all P < 0.05); miR-223-3p mimic groups had the opposite trends (all P < 0.05). siRNA-PIK3C2A + miR-223-3p mimic showed no obvious change relative to the control groups (all P > 0.05). Low expression of miR-223-3p may downregulate PIK3C2A expression, resulting in the inhibition of myocardial cell apoptosis in rats with myocardial infarction via the activation of PI3K/Akt signaling pathway.

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.

Tetrandrine attenuates left ventricular dysfunction in rats with myocardial infarction.

The present study aimed to determine whether tetrandrine could attenuate left ventricular dysfunction and remodeling in rats with myocardial infarction. Sprague-Dawley rats were randomly divided into six groups (n=5/group) as follows: i) Healthy control group; ii) sham operation group; iii) myocardial infarction model group; iv) myocardial infarction + low-dose tetrandrine group (10 mg/kg); v) myocardial infarction + medium-dose tetrandrine group (50 mg/kg); and vi) myocardial infarction + high-dose tetrandrine group (80 mg/kg). Left ventricular end-diastolic diameter (LVIDd), left ventricular end-systolic diameter (LVIDs), ejection fraction (EF%) and left ventricular fractional shortening rate (FS%) were measured using ultrasonography. The pathological changes were observed by hematoxylin and eosin (H&E) staining. Left ventricular tissue section TUNEL staining was also performed. Furthermore, the triglyceride (TG), total cholesterol (TC), high density lipoprotein (HDL) and low-density lipoprotein (LDL) in the arterial blood were examined by biochemical testing. Expression levels of intracellular Ca2+ homeostasis-related proteins including ryanodine receptor calmodulin, CaM-dependent protein kinase IIδ, protein kinase A, FK506 binding protein 12.6 were measured using western blot analysis. Ultrasonography results showed that in the myocardial infarction model rats, the levels of LVIDd and LVIDs were significantly higher; however, the levels of EF% and FS% were lower compared with those in the sham operation group, which was alleviated by tetrandrine. H&E results showed that tetrandrine alleviated the pathological characteristics of myocardial infarction model rats. Furthermore, tetrandrine significantly inhibited myocardial cell apoptosis in rats with myocardial infarction. Tetrandrine significantly inhibited the levels of TG, TC and LDL and increased the levels of HDL in the arterial blood of rats with myocardial infarction. These findings revealed that tetrandrine could attenuate left ventricular dysfunction in rats with myocardial infarction, which might be associated with intracellular Ca2+ homeostasis.

MiR-145-5p promotes myocardial cell apoptosis in rats with myocardial infarction through PI3K/Akt signaling pathway.

The aim of this study was to explore the influence of micro ribonucleic acid (miR)-145-5p on myocardial cell apoptosis in rats with myocardial infarction (MI) through the phosphatidylinositol 3-hydroxy kinase/protein kinase B (PI3K/Akt) pathway. In this study, Sprague-Dawley rats were used as research objects to establish the acute MI model in vivo. Infarction tissues and non-infarction tissues were both collected from rats. The expression level of miR-145-5p was determined using quantitative Polymerase Chain Reaction (qPCR), and the pathological changes in myocardial tissues of rats were observed through hematoxylin-eosin (HE) staining. In addition, H9c2 rat myocardial cells were cultured under hypoxia or normal oxygen concentration to simulate hypoxia in MI tissues. The changes in the expression of miR-145-5p in H9c2 cells in normal oxygen and hypoxia were determined. Meanwhile, the ratio of apoptotic cells to viable cells, and the changes in the expressions of proteins B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), Caspase-3 and Caspase-9 were evaluated through flow cytometry assay and Western blotting, respectively. The expression levels of crucial proteins in the PI3K/Akt pathway were measured as well. Additionally, H9c2 cells were transfected with miR-145-5p control and miR-145-5p mimic to evaluate cell apoptosis. QPCR results revealed that the expression level of miR-145-5p was substantially elevated in MI tissues (p<0.05). HE results indicated that the soma exhibited deformation after MI, suggesting that there were more necrotic and apoptotic cells. Compared with those cultured under normal oxygen concentration, H9c2 cells cultured in hypoxia environment exhibited significantly upregulated expression level of miR-145-5p, downregulated expression level of anti-apoptosis protein Bcl-2, upregulated level of pro-apoptosis protein Bax, activated Caspase-3 and Caspase-9, and downregulated expression level of functional proteins in the PI3K/Akt pathway (p<0.05). Furthermore, the expression levels of apoptosis-associated proteins significantly rose in H9c2 cells transfected with miR-145-5p mimic compared with those transfected with miR-145-5p control, showing statistically significant differences (p<0.05). MiR-145-5p is notably raised in MI tissues of rats. After infarction, there are evidently more apoptotic myocardial cells. The expression of miR-145-5p is markedly elevated in H9c2 rat myocardial cells in hypoxia. Compared with those cultured in normal oxygen, H9c2 cells cultured in hypoxia showed increased apoptosis. The apoptosis of myocardial cells transfected with miR-145-5p mimic is notable higher than that of myocardial cells transfected with miR-145-5p control. Moreover, the expressions of active Akt and PI3K proteins decrease remarkably. The results of this study demonstrate that miR-145-5p inactivates the PI3K/Akt pathway to promote the apoptosis of MI cells.