Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reactive oxygen species (ROS) enhance myocardial ischemia-reperfusion (I/R) injury. Ischemic preconditioning (PC) provides potent cardioprotective effects in I/R. However, it has not been elucidated whether PC diminishes ROS stress in I/R and whether PC protects the myocardium from ROS stress transmurally and homogeneously. Isolated rabbit hearts perfused with Krebs-Henseleit buffer underwent 30 min of ischemia and 60 min of reperfusion. Hemodynamic changes and myocardial damage extent were analyzed in four groups. The control group underwent I/R alone. The H2O2 group underwent I/R with H2O2 infusion (50 microM) in the first minute of reperfusion to enhance oxidative stress. The PC and H2O2+PC groups underwent 5 min of PC before control and H2O2 protocols, respectively. Extracted myocardial DNA was analyzed for 8-hydroxydeoxyguanosine (8-OHdG), an indicator of oxidative DNA damage, with the use of the HPLC-electrochemical detection method. Glutathione peroxidase (GPX) activity and the reduced form of GSH were measured by spectrophotometric assays. The myocardial infarct size was significantly reduced in the PC group (19 +/- 2%) compared with the control group (37 +/- 4%; P < 0.05), particularly in the subendocardium. H2O2 transmurally increased the infarct size by 59 +/- 4% (P < 0.05), which was significantly diminished in the H2O2+PC group (31 +/- 4%; P < 0.01). The GSH levels, but not GPX activity, were well preserved transmurally in protocols with PC. The 8-OHdG levels were significantly decreased in PC and were significantly enhanced in H2O2 (P < 0.01). These changes in oxidative DNA damage were effectively diminished by PC. In conclusion, PC enhanced the scavenging activity of GSH against ROS transmurally, reduced myocardial damage, particularly in the subendocardium, and diminished the transmural difference in myocardial infarct size.
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PMID:Ischemic preconditioning enhances scavenging activity of reactive oxygen species and diminishes transmural difference of infarct size. 1604 Jul 11

Recent studies have demonstrated that electrical uncoupling at gap junctions during ischemia is associated with cardiac Connexin-43 (Cx43) dephosphorylation. Whether oxidative stress is involved in this phenomenon still remains unclear. In the present study, we examined the influence of selenium intake on reperfusion-induced Cx43 dephosphorylation. Male Wistar rats were fed a diet containing either 0.05 mg/kg (Low-Se, n = 13) or 1.5 mg/kg (High-Se, n = 11) selenium for 8 weeks. At the end of this diet, hearts were isolated and subjected to 10 min regional ischemia followed by 10 min reperfusion. The level of dephosphorylated Cx43 was determined in tissue samples from ischemic/reperfused and non-ischemic regions of the hearts. At the end of the experiemental diet, the activity of the antioxidant enzyme glutathione peroxidase (GSH-Px) was increased in high-Se hearts compared with low-Se hearts (+ 13%; p < 0.05). After ischemia/reperfusion, in low-Se hearts, Cx43 dephosphorylation appeared significantly increased in the left ventricle compared to the non-ischemic right ventricle (+ 149%; p < 0.05). The high-Se diet significantly reduced Cx43 dephosphorylation in the left ventricle (p < 0.05 vs. low-Se diet). In conclusion, our results suggest that oxidative stress may be involved in Cx43 dephosphorylation during myocardial ischemia/reperfusion, thereby contributing to arrhythmogenesis.
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PMID:Selenium status as determinant of connexin-43 dephosphorylation in ex vivo ischemic/reperfused rat myocardium. 1624 Jun 71

The aim of the present study was to investigate the protective effect of 1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxyphenylethylamino) propane hydrochloride (DDPH) on myocardial ischemia-reperfusion (I/R) injury in rats and the mechanism of its myocardial protection. For this purpose, 50 Wistar rats were divided into five groups: sham group, control group, verapamil treated group, and two DDPH treated groups (20 and 40 mg/kg, respectively). Myocardial I/R injury model was established by reperfusion for 120 min after 40 min ischemia induced by the ligation of left descending coronary artery in rats. The influence of DDPH on myocardial infarction size was observed and the levels of myocardial enzymes in serum were measured. The activities of oxygen free radical scavenging enzymes and the content of malondialdehyde (MDA) in myocardium and serum were determined. The pathological changes of myocardial tissue were observed. The results showed that DDPH significantly diminished myocardial infarction size, reduced the release of myocardial creatine phosphokinase (CPK), lactate dehydrogenase (LDH) and glutamic oxaloacetic aminotransferase (GOT), protected the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and decreased the content of MDA in myocardium and serum as compared with the control group. The degree of myocardial injury was slighter in DDPH treated groups than in control group. These results suggest that DDPH produces a cardioprotective effect during myocardial I/R injury, which may be related to blocking calcium channels and inhibiting the formation of the oxygen free radical and subsequent peroxidation of lipid by DDPH.
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PMID:Protective effect of 1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxyphenylethylamino) propane hydrochloride on myocardial ischemia-reperfusion injury in rats. 1639 71

The effect of oleanolic acid (OA) pretreatment on myocardial ischemia-reperfusion (I-R) injury was investigated using an ex vivo rat heart model. Pretreatment with OA at daily doses (0.6 and 1.2 mmol/kg) for 3 days significantly protected against I-R injury in isolated rat hearts, as evidenced by the decrease in the extent of lactate dehydrogenase (LDH) leakage and improvement in contractile force recovery. The cardioprotection was associated with a slight increase in mitochondrial reduced glutathione (GSH) level and a significant increase in mitochondrial alpha-tocopherol (alpha-TOC) level, when compared with the unpretreated I-R group. To further investigate the mechanism of myocardial protection, pretreatment with a single dose of OA (1.2 mmol/kg) produced a time-dependent protection against myocardial I-R injury as assessed by LDH leakage, with the maximum extent of protection occurring at 48 hour post-dosing. The maximum cardioprotection was associated with parallel increases in mitochondrial GSH and alpha-TOC levels in ischemic-reperfused hearts, with the stimulation of the alpha-TOC level being optimal. Furthermore, buthionine sulfoximine/phorone (BSO/PHO) treatment, while abolishing the enhancing effect of OA on mitochondrial GSH, did not completely abrogate the cardioprotection against I-R injury. The remnant cardioprotection was associated with an increase in mitochondrial alpha-TOC level, when compared with the unpretreated I-R group with BSO/PHO. The results suggest that the cardioprotection afforded by OA pretreatment against I-R injury may at least in part be attributed to the enhancement of mitochondrial antioxidant mechanism mediated by GSH and alpha-TOC, particularly under I-R conditions. Abbreviations. BSO:buthionine sulfoximine GSH:reduced glutathione I-R:ischemia-reperfusion alpha-LA:alpha-lipoic acid LDH:lactate dehydrogenase OA:oleanolic acid PHO:phorone alpha-TOC:alpha-tocopherol.
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PMID:Oleanolic acid protects against myocardial ischemia-reperfusion injury by enhancing mitochondrial antioxidant mechanism mediated by glutathione and alpha-tocopherol in rats. 1653 26

This study examined the potential deleterious effect of high-dose nitroglycerin (NTG) on cardiac function and cellular injury after ischemia (30 min) and reperfusion (120 min) in isolated perfused rat hearts. Low-dose (0.75 microg/h), medium-dose (3.75 microg/h), high-dose (15 microg/h) NTG or high-dose NTG plus glutathione (GSH, 1 mmol/L) was administrated at the time of reperfusion. Administration of high-dose NTG significantly exacerbated cardiac reperfusion injury as evidenced by increased creatine kinase and lactate dehydrogenase activity in coronary effluent, increased cardiomyocyte apoptosis and necrosis, and decreased cardiac function recovery after reperfusion. Compared with the vehicle group, formation of nitrotyrosine, a footprint for peroxynitrite (ONOO) production, was markedly increased in the hearts treated with medium-dose or high-dose NTG. Most interestingly, cotreatment with GSH blocked high-dose NTG-induced ONOO formation and attenuated myocardial ischemia/reperfusion injury. Taken together, our present results demonstrated that administration of high-dose NTG aggravated, rather than attenuated myocardial ischemia/reperfusion injury likely via increasing ONOO formation. Coadministration of GSH may reverse the advert action of high-dose NTG.
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PMID:Glutathione reverses peroxynitrite-mediated deleterious effects of nitroglycerin on ischemic rat hearts. 1663 83

Reactive oxygen species (ROS) enhance myocardial ischemia-reperfusion (I/R) injury. Ebselen, a seleno-organic glutathione peroxidase (GPx) mimetic, has a protective effect against tissue injury induced by ROS. However, the cardio-protective effect of orally administered ebselen has never been investigated in cardiac I/R injury. We investigated the effects and mechanisms of orally administered ebselen on experimental myocardial infarction. Isolated perfused rabbit hearts underwent 30 min of global ischemia and 60 min of reperfusion, with or without oral administration of ebselen 24 h before I/R, with or without enhanced oxidative stress by H202 infusion for the first 1 min of reperfusion. The recovery of left ventricular developed pressure (LVDP) was significantly improved, and the myocardial infarct size was significantly reduced by ebselen. The recovery of LVDP and the myocardial infarct size were markedly aggravated by H202 infusion. These enhancements by H202 were dose-dependently suppressed by ebselen, along with a reduction in myocardial 8-hydroxydeoxyguanosine levels, a marker for oxidative DNA damage. The myocardial reduced glutathione (GSH) level was preserved by ebselen. Ebselen markedly enhanced myocardial heat shock protein (HSP) 72 expression. The cardioprotective effect of ebselen-induced HSP72 was confirmed by MTT assay in isolated cardiomyocytes using KNK437, a novel HSP inhibitor. In conclusion, an oral administration of ebselen 24 h before I/R provided excellent cardioprotective effects, at least in part through HSP72 induction and GSH preservation.
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PMID:Oral pretreatment with ebselen enhances heat shock protein 72 expression and reduces myocardial infarct size. 1734 91

The study was designed to investigate the effect of progesterone and its gender based variation on myocardial ischemia/reperfusion (I/R) injury in rats. Adult Sprague Dawley rats were divided into vehicle treated reperfusion injury group male (I/R-M), female (I/R-F), ovariectomised (I/R-OVR) and progesterone treatment (I/R-M+PG, I/R-F+PG, I/R-OVR+PG) groups, respectively. I/R injury was produced by occluding the left descending coronary artery (LCA) for 1 h and followed by re-opening for 1 h. Progesterone (2 mg kg(-1) i.p.) was administered 30 min after induction of ischemia. Hemodynamic parameters (+/-dp/dt, MAP), heart rate, ST-segment elevation and occurrence of ventricular tachycardia (VT) were measured during the I/R period. The myocardial infarct area, oxidative stress markers, activities of myeloperoxidase (MPO) and creatine kinase (CK) were determined after the experiment along with the assessment of the effect on apoptotic activity by using DNA fragmentation analysis. Histological observations were carried out on heart tissue. Treatment with progesterone significantly (P<0.05) reduced infarct area, lipid peroxidation (LPO) level and activity of MPO in females (I/R-F+PG) as compared to ischemic females (I/R-F). Progesterone significantly (P<0.001, P<0.05) inhibited serum CK activity and incidences of VT in female rats. Superoxide dismutase (SOD) activity, reduced glutathione (GSH) levels were significantly elevated (P<0.05) in I/R-F+PG group. Internucleosomal DNA fragmentation was less in I/R-F+PG group when compared to I/R-F group. The ischemic male and ovariectomised (I/R-M and I/R-OVR) counterparts did not show any significant change after progesterone treatment. In conclusion, the cardioprotective effect of progesterone on myocardial I/R injury induced damage is based on gender of the animal. The protective effect could be mediated by attenuation of inflammation and its possible interaction with endogenous estrogen.
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PMID:Gender specific effect of progesterone on myocardial ischemia/reperfusion injury in rats. 1758 47

Mitochondrial superoxide (O2.) is an important mediator of ischemia/reperfusion (I/R) injury. The O2. generated in mitochondria also acts as a redox signal triggering cellular apoptosis. The enzyme succinate ubiquinone reductase (SQR or complex II) is one of the major mitochondrial components hosting regulatory thiols. Here the intrinsic protein S-glutathionylation (PrSSG) at the 70-kDa FAD-binding subunit of SQR was detected in rat heart and in isolated SQR using an anti-GSH monoclonal antibody. When rats were subjected to 30 min of coronary ligation followed by 24 h of reperfusion, the electron transfer activity (ETA) of SQR in post-ischemic myocardium was significantly decreased by 41.5 +/- 2.9%. The PrSSGs of SQR-70 kDa were partially or completely eliminated in post-ischemic myocardium obtained from in vivo regional I/R hearts or isolated global I/R hearts, respectively. These results were further confirmed by using isolated succinate cytochrome c reductase (complex II + complex III). In the presence of succinate, O2. was generated and oxidized the SQR portion of SCR, leading to a 60-70% decrease in its ETA. The gel band of the S-glutathionylated SQR 70-kDa polypeptide was cut out and digested with trypsin, and the digests were subjected to liquid chromatography/tandem mass spectrometry analysis. One cysteine residue, Cys(90), was involved in S-glutathionylation. These results indicate that the glutathione-binding domain, (77)AAFGLSEAGFNTACVTK(93) (where underline indicates Cys(90)), is susceptible to redox change induced by oxidative stress. Furthermore, in vitro S-glutathionylation of purified SQR resulted in enhanced SQR-derived electron transfer efficiency and decreased formation of the 70-kDa-derived protein thiyl radical induced by O2. . Thus, the decreasing S-glutathionylation and ETA in mitochondrial complex II are marked during myocardial ischemia/reperfusion. This redox-triggered impairment of complex II occurs in the post-ischemic heart and should be useful to identify disease pathogenesis related to reactive oxygen species-induced mitochondrial dysfunction.
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PMID:Mitochondrial complex II in the post-ischemic heart: oxidative injury and the role of protein S-glutathionylation. 1784 55

The purpose of this study is to examine the antiarrhythmic and antioxidant effects of tamoxifen, one of the selective estrogen modulators, in ovariectomized rats subjected to myocardial ischemia-reperfusion (I/R) injury. A month after ovariectomy, rats were divided into four groups: (I) ovariectomized controls without any treatment, (II) ovariectomized rats treated with vehicle dimethylsulfoxide (DMSO), (III)-(IV) ovariectomized rats treated with tamoxifen 1 or 10 mg/kg,sc daily for 14 days. To produce arrhythmia, the left main coronary artery was occluded for 7 min, followed by 7 min of reperfusion. The blood pressure (BP), heart rate (HR), electrocardiography (ECG) was recorded before and during the ischemia-reperfusion period. The blood levels of malondialdehyde (MDA), creatine kinase (CK), glutathione (GSH), glutathione peroxidase (GSH-Px), glutathione reductase (GR), and catalase (CAT) were measured after the rats were killed. Tamoxifen reduced the incidence of ventricular tachycardia (VT) on ischemia and reperfusion as well as the incidence and duration of reversible ventricular fibrillation (VF) on reperfusion. I/R injury caused a significant fall in GSH, GSH-Px as well as an increase in MDA and CK levels in the control group when compared to tamoxifen treated groups. The changes in levels of CAT and GR were however, not significant. In conclusion, our findings suggest that tamoxifen has cardioprotective effects against I/R injury in rats, likely its antioxidant properties.
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PMID:Effects of tamoxifen on myocardial ischemia-reperfusion injury model in ovariectomized rats. 1797 64

Increased levels of reactive oxygen species, alterations in nitric oxide synthesis, and increased migration of neutrophils to the ischemic tissue play an important role in the pathophysiology of myocardial ischemia-reperfusion (IR) injury. In this study, we have evaluated the effects of melatonin on myeloperoxidase (MPO) activity, tissue glutathione (GSH), lipid peroxidation levels, and blood pressure in L-NAME-induced hypertensive rats with or without IR. NOS inhibitor L-NAME was administrated before inducing cardiac ischemia for 15 days intraperitoneally. For the cardiac ischemia, the left coronary artery was ligated for 30 min, and reperfusion was performed for 120 min after the ischemia. L-NAME treatment in non-ischemic animals increased blood pressure and lipid peroxidation, and decreased glutathione level in myocardial tissue significantly as compared with non-L-NAME-treated animals. Melatonin reversed L-NAME-induced blood pressure elevation and oxidative changes. Cardiac IR increased MDA levels and MPO activity and decreased GSH levels as compared with non-ischemic animals. L-NAME treatment did not change in IR-induced MDA and GSH levels as compared with ischemic control animals. However, MPO activity was significantly higher than control ischemic animals. MDA levels and MPO activity resulting from ischemic injury in melatonin-treated animals were significantly less than L-NAME-treated animals. Taken together-the ischemic and non-ischemic control and melatonin-treated animals-this study shows that neutrophil migration plays an important role on the development of ischemic injury in hypertensive rats.
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PMID:Melatonin protects myocardium from ischemia-reperfusion injury in hypertensive rats: role of myeloperoxidase activity. 1885 70


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