This study aimed to explore the mechanism of resveratrol(RES) pretreatment in improving mitochondrial function and alleviating myocardial ischemia-reperfusion(IR) injury by inhibiting stromal interaction molecule 2(STIM2) through microRNA-20 b-5 p(miR-20 b-5 p). Ninety rats were randomly assigned into sham group, IR group, IR+RES(50 mg·kg~(-1) RES) group, IR+RES+antagomir NC(50 mg·kg~(-1) RES+80 mg·kg~(-1) antagomir NC) group, and IR+RES+miR-20 b-5 p antagomir(50 mg·kg~(-1) RES+80 mg·kg~(-1) miR-20 b-5 p antagomir) group, with 18 rats/group. The IR rat model was established by ligation of the left anterior descending coronary artery. Two weeks before the operation, rats in the IR+RES group were intraperitoneally injected with 50 mg·kg~(-1) RES, and those in the sham and IR groups were injected with the same dose of normal saline, once a day. Ultrasonic instrument was used to detect the left ventricular internal diameter at end-diastole(LVIDd) and left ventricular internal diameter at end-systole(LVIDs) of rats in each group. The 2,3,5-triphenyte-trazoliumchloride(TTC) method and hematoxylin-eosin(HE) staining were employed to detect the myocardial infarction area and histopathology, respectively. Real-time quantitative PCR(qRT-PCR) was carried out to detect the expression of miR-20 b-5 p in myocardial tissue. Oxygen glucose deprivation/reoxygenation(OGD/R) was performed to establish an OGD/R model of H9 c2 cardiomyocytes. CCK-8 assay was employed to detect H9 c2 cell viability. H9 c2 cells were assigned into the control group, OGD/R group, OGD/R+RES group(25 μmol·L~(-1)), OGD/R+RES+inhibitor NC group, OGD/R+RES+miR-20 b-5 p inhibitor group, mimic NC group, miR-20 b-5 p mimic group, inhibitor NC group, and miR-20 b-5 p inhibitor group. Flow cytometry was employed to detect cell apoptosis. Western blot was employed to detect the expression of B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), cleaved-cysteine proteinase 3(cleaved-caspase-3), and STIM2 in cells. The mitochondrial membrane potential(MMP) assay kit, reactive oxygen species(ROS) assay kit, and adenosine triphosphate(ATP) assay kit were used to detect the MMP, ROS, and ATP levels, respectively. Dual luciferase reporter gene assay was adopted to verify the targeting relationship between miR-20 b-5 p and STIM2. Compared with the sham group, the modeling of IR increased the myocardial infarction area, LVIDd, LVIDs, and myocardial pathology and down-regulated the expression of miR-20 b-5 p(P<0.05). These changes were alleviated in the IR+RES group(P<0.05). The IR+RES+miR-20 b-5 p antagomir group had higher myocardial infarction area, LVIDd, LVIDs, and myocardial pathology and lower expression of miR-20 b-5 p than the IR+RES group(P<0.05). The OGD/R group had lower viability of H9 c2 cells than the control group(P<0.05) and the OGD/R+RES groups(25, 50, and 100 μmol·L~(-1))(P<0.05). Additionally, the OGD/R group had higher H9 c2 cell apoptosis rate, protein levels of Bax and cleaved caspase-3, and ROS level and lower Bcl-2 protein, MMP, and ATP levels than the control group(P<0.05) and the OGD/R+RES group(P<0.05). The OGD/R+RES+miR-20 b-5 p inhibitor group had higher H9 c2 cell apoptosis rate, protein levels of Bax and cleaved-caspase 3, and ROS level and lower Bcl-2 protein, MMP, and ATP levels than the OGD/R+RES group(P<0.05). miR-20 b-5 p had a targeting relationship with STIM2. The expression of STIM2 was lower in the miR-20 b-5 p mimic group than in the mimic NC group(P<0.05) and lower in the inhibitor NC group than in the miR-20 b-5 p inhibitor group(P<0.05). RES pretreatment can inhibit the expression of STIM2 by promoting the expression of miR-20 b-5 p, thereby improving the function of mitochondria and alleviating myocardial IR damage.
Animals ; Rats ; Adenosine Triphosphate ; Antagomirs/metabolism* ; bcl-2-Associated X Protein/metabolism* ; Caspase 3/metabolism* ; Glucose/metabolism* ; MicroRNAs/metabolism* ; Mitochondria, Heart/drug effects* ; Myocardial Infarction/drug therapy* ; Myocardial Reperfusion Injury/drug therapy* ; Myocytes, Cardiac ; Oxygen/metabolism* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Rats, Sprague-Dawley ; Reactive Oxygen Species/metabolism* ; Resveratrol/therapeutic use* ; Stromal Interaction Molecule 2/metabolism*

OBJECTIVE: To investigate the effects of salvianolic acid A (SAA) on cardiomyocyte apoptosis and mitochondrial dysfunction in response to hypoxia/reoxygenation (H/R) injury and to determine whether the Akt signaling pathway might play a role. METHODS: An in vitro model of H/R injury was used to study outcomes on primary cultured neonatal rat cardiomyocytes. The cardiomyocytes were treated with 12.5, 25, 50 μg/mL SAA at the beginning of hypoxia and reoxygenation, respectively. Adenosine triphospate (ATP) and reactive oxygen species (ROS) levels were assayed. Cell apoptosis was evaluated by flow cytometry and the expression of cleaved-caspase 3, Bax and Bcl-2 were detected by Western blotting. The effects of SAA on mitochondrial dysfunction were examined by determining the mitochondrial membrane potential (△Ψm) and mitochondrial permeability transition pore (mPTP), followed by the phosphorylation of Akt (p-Akt) and GSK-3β (p-GSK-3β), which were measured by Western blotting. RESULTS: SAA significantly preserved ATP levels and reduced ROS production. Importantly, SAA markedly reduced the number of apoptotic cells and decreased cleaved-caspase 3 expression levels, while also reducing the ratio of Bax/Bcl-2. Furthermore, SAA prevented the loss of △Ψm and inhibited the activation of mPTP. Western blotting experiments further revealed that SAA significantly increased the expression of p-Akt and p-GSK-3β, and the increase in p-GSK-3β expression was attenuated after inhibition of the Akt signaling pathway with LY294002. CONCLUSION SAA has a protective effect on cardiomyocyte H/R injury; the underlying mechanism may be related to the preservation of mitochondrial function and the activation of the Akt/GSK-3β signaling pathway.
Adenosine Triphosphate ; analysis ; Animals ; Animals, Newborn ; Caffeic Acids ; pharmacology ; Cell Hypoxia ; Cells, Cultured ; Glycogen Synthase Kinase 3 beta ; physiology ; Lactates ; pharmacology ; Mitochondria, Heart ; drug effects ; physiology ; Mitochondrial Membrane Transport Proteins ; drug effects ; Myocytes, Cardiac ; drug effects ; Proto-Oncogene Proteins c-akt ; physiology ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species ; metabolism ; Signal Transduction ; physiology

OBJECTIVE: To investigate whether CaN-NFAT3 pathway mediates the protective effects of aldehyde dehydrogenase (ALDH) 2 in high glucose-treated neonatal rat ventricular myocytes. METHODS: The ventricular myocytes were isolated from the heart of neonatal (within 3 days) SD rats by enzyme digestion and cultured in the presence of 5-Brdu. After reaching confluence, the cultured ventricular myocytes were identified using immunofluorescence assay for -SA protein. The cells were then cultured in either normal (5 mmol/L) or high glucose (30 mmol/L) medium in the presence of ALDH2 agonist Alda-1, ALDH 2 inhibitor Daidzin, or Alda-1 and NFAT3 inhibitor (11R-VIVIT). Fluorescent probe and ELISA were used to detect intracellular Ca concentration and CaN content, respectively; ALDH2, CaN and NFAT3 protein expressions in the cells were detected using Western blotting. RESULTS: Compared with cells cultured in normal glucose, the cells exposed to high glucose showed a significantly decreased expression of ALDH2 protein ( < 0.05) and increased expressions of CaN ( < 0.05) and NFAT3 proteins with also increased intracellular CaN and Ca concentrations ( < 0.01). Alda-1 treatment significantly lowered Ca concentration ( < 0.05), intracellular CaN content ( < 0.01), and CaN and NFAT3 protein expressions ( < 0.05), and increased ALDH2 protein expression ( < 0.05) in high glucose- exposed cells; Daidzin treatment significantly increased Ca concentration ( < 0.01) and intracellular CaN content ( < 0.05) in the exposed cells. Compared with Alda-1 alone, treatment of the high glucose-exposed cells with both Alda-1 and 11R-VIVIT did not produce significant changes in the expression of ALDH2 protein (>0.05) but significantly reduced the expression of NFAT3 protein ( < 0.05). CONCLUSIONS Mitochondrial ALDH2 protects neonatal rat cardiomyocytes against high glucose-induced injury possibly by negatively regulating Ca-CaN-NFAT3 signaling pathway.
Aldehyde Dehydrogenase, Mitochondrial ; antagonists & inhibitors ; metabolism ; Animals ; Animals, Newborn ; Benzamides ; pharmacology ; Benzodioxoles ; pharmacology ; Calcium ; metabolism ; Cells, Cultured ; Culture Media ; Enzyme Inhibitors ; pharmacology ; Glucose ; administration & dosage ; pharmacology ; Isoflavones ; pharmacology ; Mitochondria, Heart ; enzymology ; Myocytes, Cardiac ; drug effects ; metabolism ; NFATC Transcription Factors ; metabolism ; Nuclear Pore Complex Proteins ; metabolism ; Rats ; Rats, Sprague-Dawley

Sheng-Mai-San (SMS), a well-known Chinese medicinal plant formula, is widely used for the treatment of cardiac diseases characterized by deficiency of Qi and Yin syndrome. A mouse chronic intermittent hypoxia (CIH) model was established to mimic the primary clinical features of deficiency of Qi and Yin syndrome. Mice experienced CIH for 28 days (nadir 7% to peak 8% oxygen, 20 min per day), resulting in left ventricle (LV) dysfunction and structure abnormalities. After administration of SMS (0.55, 1.1, and 5.5 g·kg(-1)·d(-1)) for four weeks, improved cardiac function was observed, as indicated by the increase in the ejection fraction from the LV on echocardiography. SMS also preserved the structural integrity of the LV against eccentric hypotrophy, tissue vacuolization, and mitochondrial injury as measured by histology, electron microscopy, and ultrasound assessments. Mechanistically, the antioxidant effects of SMS were demonstrated; SMS was able to suppress mitochondrial apoptosis as indicated by the reduction of several pro-apoptotic factors (Bax, cytochrome c, and cleaved caspase-3) and up-regulation of the anti-apoptosis factor Bcl-2. In conclusion, these results demonstrate that SMS treatment can protect the structure and function of the LV and that the protective effects of this formula are associated with the regulation of the mitochondrial apoptosis pathway.
Animals ; Antioxidants ; pharmacology ; therapeutic use ; Apoptosis ; Cardiomyopathies ; drug therapy ; etiology ; Caspase 3 ; metabolism ; Cytochromes c ; metabolism ; Disease Models, Animal ; Drug Combinations ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Heart Ventricles ; drug effects ; pathology ; physiopathology ; Hypoxia ; Male ; Mice, Inbred ICR ; Mitochondria ; drug effects ; metabolism ; Myocardium ; pathology ; Oxygen ; metabolism ; Phytotherapy ; Qi ; Up-Regulation ; Ventricular Dysfunction, Left ; drug therapy ; etiology ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo investigate the influence of total flavonoids of Elsholtzia splendens (TFES) on isolated ischemia/reperfusion rat hearts and its underlying mechanisms.

METHODSHearts isolated from male SD rats were perfused on the Langendorff apparatus and subjected to global ischemia for 30 min followed by 120 min of reperfusion. The cardiac infarct size was measured by TTC staining. Hemodynamic parameters and the level of lactate dehydrogenase (LDH) in the coronary effluent were measured. Absorbance at 520 nm was determined in isolated cardiac mitochondria exposed to 200 micromol/L CaCl2 to detect the opening of the mitochondrial permeability transition pore.

RESULTSPretreatment with TFES (1, 10, 100 microg/ml) for 5 min decreased infarct size and LDH release and improved the recovery of the left ventricular developed pressure. In mitochondria, the decrease of absorbance at 520 nm evoked by CaCl2 was greatly inhibited by TFES.

CONCLUSIONTFES prevents myocardial ischemia/reperfusion injury, and this cardioprotective effect is probably via inhibiting mitochondrial permeability transition pore opening.

Animals ; Cardiotonic Agents ; pharmacology ; Disease Models, Animal ; Flavones ; pharmacology ; In Vitro Techniques ; Lamiaceae ; chemistry ; Male ; Mitochondria, Heart ; drug effects ; Mitochondrial Membrane Transport Proteins ; drug effects ; Myocardial Reperfusion ; Myocardial Reperfusion Injury ; prevention & control ; Rats ; Rats, Sprague-Dawley

Animals ; Codonopsis ; Drugs, Chinese Herbal ; pharmacology ; Fatigue ; Male ; Mitochondria, Heart ; drug effects ; metabolism ; Oxidative Stress ; Physical Conditioning, Animal ; Rats ; Rats, Sprague-Dawley ; Selenium

OBJECTIVETo study the phosphorylation activity of mitochondrial signal transducer and activator of transcription 3 (STAT3) in the myocardium of rats with selenium deficiency and its association with myocardial injury.

METHODSThirty-six rats were randomized into normal control group (n=18) and selenium deficiency model group (n=18) for feeding with normal and low-selenium chow, respectively, for 20, 30 and 40 weeks. The cardiac function of the rats was evaluated by carotid artery intubation, and the damage of cardiac mitochondria was observed under electron microscopy. The cardiac mitochondria were extracted for assessing succinate dehydrogenase and cytochrome C oxidase activities, and the protein expressions of phosphorylated and total STAT3 were detected.

RESULTSCompared with the corresponding control groups, the rats in the model group showed significantly decreased cardiac function with obvious structural and functional damage of the cardiac mitochondria (P<0.05), which aggravated as the low-selenium feeding time extended (P<0.05). The rats in the model group also showed significantly decreased mitochondrial STAT3 activity (p-STAT3/STAT3) in the myocardium as the low-selenium feeding time prolonged (P<0.05). Pearson linear correlation analysis showed that the activity of cardiac mitochondrial STAT3 had positive correlations with the left ventricular systolic pressure, maximal increased rate of the left ventricular pressure, and the activities of succinate dehydrogenase and cytochrome C oxidase (P<0.01).

CONCLUSIONSelenium deficiency down-regulates the activity of mitochondrial STAT3 in rat heart to contribute to cardiac mitochondrial injury and the progression of heart failure.

Animals ; Diet ; Electron Transport Complex IV ; metabolism ; Female ; Heart Injuries ; metabolism ; Male ; Mitochondria, Heart ; drug effects ; metabolism ; Rats ; Rats, Sprague-Dawley ; STAT3 Transcription Factor ; metabolism ; Selenium ; deficiency ; pharmacology ; Signal Transduction ; Succinate Dehydrogenase ; metabolism

OBJECTIVETo study pathological and therapeutical problems concerning myocardial cell mitochondria changes during myocardial cell hypertrophy by culturing rat primary myocardial cells.

METHODPrimary myocardial cells were seperated and cultured together with angiotensin II (Ang II) for 72 or 96 hours. The total protein content with the BCA method and the photography and measurement of cell diameter with inverted microscope reflected myocardial cell proliferation. The mitochondrial membrane potential (Delta Psi m) with fluorescence microscope, the mitochondrial single amine oxidase (MAO) activity with spectrophotometer, the mitochondrial cytochrome oxidase (COX) activity and the injury percentage of mitochondrial outer membrane with microplate reader and the contents of ATP, ADP, AMP with high performance liquid chromatography reflected the injury and energy metabolism of myocardial cell mitochondrial structure and function when being cultured together with Ang II. On that basis, cells were treated with Astragali Radix injection and valsartan for observing pharmacological effects on mitochondrial structure and function in restructured myocardial cells.

RESULTIn 72 h and 96 h, compare with the control group, the model group showed significantly increased total protein content and enlarged myocardial cell diameter. During the course of proliferation, the myocardial cell MAO activity and the injury percentage of mitochondrial outer membrane were significantly increased, with significant decrease in mitochondrial COX activity, mitochondrial Delta Psi m and the content of ATP, ADP and rise in the content of AMP. Astragali Radix injection and valsartan reduced myocardial cell total protein content and cell diameter caused by Ang II, decreased myocardial cell MAO activity, significantly increased mitochondrial COX activity and the content of ATP and ADP, and decreased the content of AMP.

CONCLUSIONDuring the process of myocardial hypertrophy, the injury of mitochondrial structure and function and the changes in myocardial cell energy metabolism injury occurred after the injury of mitochondria. Astragali Radix injection and valsartan can reverse myocardial cell mitochondrial structure and function during myocardial cell hypertrophy caused by Ang II. Reversion of myocardial cell hypertrophy and restructuring of myocardial cells helps improve energy metabolism of the myocardial cells.

Animals ; Astragalus Plant ; chemistry ; Cells, Cultured ; Drugs, Chinese Herbal ; administration & dosage ; therapeutic use ; Female ; Hypertrophy ; drug therapy ; Injections ; Male ; Membrane Potential, Mitochondrial ; drug effects ; Mitochondria, Heart ; drug effects ; Myocytes, Cardiac ; drug effects ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the intervention effect and the possibly mechanism of the glutamine (Gln) on the opening change of the permeability transition pore (PTP) in the myocardial mitochondrial membrane under the overtraining state.

METHODS30 SD rats were randomly divided into 3 groups (n = 10): control group (CG group), overtraining group (OG group) and supplementary (Gln) + overtraining group group). Spectrophotometry was used to test the openness of the permeability transition pore in the myocardial mitochondrial membrane. Electrochemistry was used to test the malondialdehyde (MDA) and the glutathione (GSH) content and the phospholipase A2 (PLA2) activity.

RESULTSOG group compared with the GOG group, the absorbance (A0) and the absorbance change (Delta A) were decreased significantly (P < 0.05). Rh123 fluorescence (F0) intensity was significantly increased (P < 0.05). Rhodamine123 (Rh123) fluorescence change (delta F) was significantly decreased (P < 0.05). Compared with the GOG, the mitochondrial GSH was significantly decreased (P < 0.05), the PLA2 activity and the content of MDA were significantly increased (P <0.05).

CONCLUSIONOvertraining could lead to opening increase of permeability transition pore in the myocardial mitochondrial membrane, after overtraining, the production of the reactive oxygen species (ROS) and PLA2 activity were increased, GSH content was decreased. But added exogenous Gln had a significant intervention effect for these changes.

Animals ; Glutamine ; pharmacology ; Glutathione ; metabolism ; Male ; Mitochondria, Heart ; drug effects ; physiology ; Mitochondrial Membrane Transport Proteins ; metabolism ; Mitochondrial Membranes ; drug effects ; physiology ; Myocardium ; metabolism ; Permeability ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species ; metabolism

OBJECTIVETo investigate the effect of exogenous carnitine on function of respiratory chain and antioxidant capacity in mitochondria of myocardium in rats.

METHODSForty male Wistar rats were randomized to 4 groups (n = 10): static control (C), supplementation of carnitine (LC), exercise-training (T) and training with supplementation of carnitine (TLC). LC and TLC animals were perfused carnitine by the dose of 300 mg/kg bw x d. T and TLC animals were forced to performed 6-week treadmill training. Heart were prepared immediately after exhaustive running. Myocardium mitochondria was extracted by differential centrifugation. Spectrophotometric analysis was used to evaluate activities of respiratory chain complex (C) I -IV and superoxide dismutase (SOD), malondialdehyde (MDA) level in myocardium mitochondria.

RESULTSTo compare with C group, C I and C IV activity in LC, T and TLC group were increased significantly (P < 0.05, P < 0.01), CII and C III activity in T and TLC group were increased significantly (P < 0.05, P < 0.01); to compare with LC group, C I - IV activity in TLC group were increased significantly (P < 0.05, P < 0.01); to compare with T group, CI and C IV activity in TLC group increased significantly (P < 0.05). To compare with C group, SOD activity increased remarkably, MDA was remarkably lower (P < 0.05, P < 0.01) in LC, T and TLC group; To compare with LC and T group, SOD activity increased remarkably, MDA was remarkably lower (P < 0.05) in TLC group.

CONCLUSIONCarnitine and training could improve function of respiratory chain and increased antioxidant capacity in myocardium mitochondria, there was better function of cooperation between carnitine and training.

Animals ; Antioxidants ; metabolism ; Carnitine ; pharmacology ; Electron Transport ; Male ; Malondialdehyde ; metabolism ; Mitochondria, Heart ; drug effects ; metabolism ; physiology ; Physical Conditioning, Animal ; physiology ; Rats ; Rats, Wistar ; Superoxide Dismutase ; metabolism