OBJECTIVETo study the effects of dopamin receptors-2 (DR2) on myocardial ischemic postconditioning and explore its underlying mechanisms.

METHODSThe myocardial ischemic postconditioning (PC) model was established in cultured primary rat neonatal cardiomyocytes which were then randomly assigned in the following groups: Nomial control group, Isehemia/reperfusion (L'R) group, PC (ischemic postconditioning) group, PC + Bro (Bromocriptine, a DB2 antagonist) group, PC + Hal (Haloperidol, a DB2 repressor) and PC + Hal + Bro groups. The lactate dehydrogenase (LDH) and superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in cell medium were analyzed by colorunetry. The cell ultrastructure changes were observed by transmission electron microscope. The cell apoptosis was analyzed using flowcytometiy. The protein expression level of D112 and activity of p-p38 and p-JNK were detected by Western blot.

RESULTSCompared with the nonnal control group, hR increased the protein expression level of DB2, enhanced LDH activity and MDA content, promoted cell injury and apoptosis, decreased SOD activity, up-regulated the activity of p-p38 and p-JNK. Compared with the hR group, although PC further increased the expression of DR2 protein, it decreased LDH activity and MDA content, cell injury and apoptosis, increased SOD activity, down-regulated activity of p-p38 and p-JNK. Bromocriptine treatment further enhanced PC-induced canlioprotective effect, yet Hal addition attenuated this enhancing effect exerted by bromocriptine.

CONCLUSIONThe activation of DB2 is involved in the protective effect of ischemic postconditioning on myocardial ischemia/reperfusion injury through down-regulating the activity of p-p38 and p-JNK.

Animals ; Apoptosis ; Cells, Cultured ; Ischemic Postconditioning ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Myocardial Reperfusion Injury ; prevention & control ; Myocytes, Cardiac ; pathology ; Rats ; Rats, Wistar ; Receptors, Dopamine D2 ; physiology ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo study the protected effect of Yindan Xinnaotong capsule (YDXNTC) and main components compatibility on myocardium ischemia/reperfusion injury.

METHODGlobal ischemia/reperfusion was adopted to induce myocardial ischemia/reperfusion injury (MIRI) in isolated rat heart. Sprague-Dawley (SD) rats were divided into control, model, YDXNTC, Ginkgo biloba extract (GBE) group, ethanol extract of Salvia miltiorrhiza (SM-E) group, aqueous extract of Salvia miltiorrhiza (SM-H) group, mixed compatibility of other components in YDXNTC (MC), GBE and SM-E compatibility (GSEC), GBE and SM-H compatibility (GSHC), and SM-E and SM-H compatibility (SEHC). During the experiment, electrocardiogram was recorded to observe cardiac arrest time, heart resuscitation time, regaining normal rhythm time, the incidence and duration of arrhythmias (VT/VF). At the end of reperfusion, hearts were arrested and homogenated to assay the activity of superoxide dismutase (SOD), and the content of malondialdehyde (MDA), lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), cardiac troponin I.

RESULT(1) YDXNTC, SM-E, SM-H and MC elevated cardiac arrest time, also reduced rebeating time, restoring normal rhythm time as well as the duration of arrhythmia, but no remarkable impact on VT/VF occurrence. GBE was effective for incidence of VT/VF, also achieved good effect on shortening rebeating time, restoring normal rhythm time and arrhythmia duration. Likewise, obviously reduced rebeating time, restoring normal rhythm time and arrhythmia duration, and evaluated cardiac arrest time were also exhibited in compatibility groups except that no lengthened cardiac arrest time was detected in GSHC. And the incidence of VT/VF was decreased by GSEC. (2) YDXNT, ginkgo biloba extract (GBE), ethanol extract of salvia miltiorrhiza (SM-E), GBE and SM-E compatibility (GSEC), and SM-E and aqueous extract of salvia miltiorrhiza (SM-H) compatibility (SEHC) could improved SOD and decreased MDA level SM-H, mixed compatibility of other elements in YDXNTC (MC) and GBE and SM-H compatibility (GSHC) showed a role on MDA reduction. (3) LDH was declined by YDXNT and SM-H. CK-MB was reduced by GBE, SM-E, SM-H, and GSEC. (4) The release of cTnI was only inhibited by GSEC.

CONCLUSIONYDXNTC, primary materials and main components compatibility has a certain protection effect on MIRI, its mechanism may be related to antioxidant and calcium overload reduction.

Animals ; Arrhythmias, Cardiac ; physiopathology ; prevention & control ; Capsules ; Creatine Kinase, MB Form ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Electrocardiography ; Ginkgo biloba ; chemistry ; Heart ; drug effects ; physiopathology ; In Vitro Techniques ; L-Lactate Dehydrogenase ; metabolism ; Male ; Malondialdehyde ; metabolism ; Myocardial Reperfusion Injury ; metabolism ; physiopathology ; prevention & control ; Myocardium ; metabolism ; pathology ; Phytotherapy ; Plant Extracts ; pharmacology ; Protective Agents ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Salvia miltiorrhiza ; chemistry ; Superoxide Dismutase ; metabolism ; Troponin I ; metabolism

OBJECTIVETo observe the protective effect of Yixinshu capsule on myocardial ischemia reperfusion injury (MIRI) in SD rats.

METHODSixty healthy SD rats were randomized into six groups: sham group, MIRI model group, Xinsuning capsule group, low, middle or high dose Yixinshu capsule. Acute MIRI rat models were created by reperfusion for 120 min after anterior interventricular branch of the left coronary artery for 30 min. The serum creatine kinase (CK), lactic dehydrogenase (LDH), aspartate aminotransferase (AST) and malondialdehyde(MDA), blood viscosity, and infarction area of myocardium were determined.

RESULTYixinshu capsule could reduce serum CK, LDH, AST and LDH activity, improve the blood viscosity, and reduced the myocardial infarct size.

CONCLUSIONYixinshu capsule can protect against MIRI in rats.

Animals ; Blood Viscosity ; drug effects ; Capsules ; Drugs, Chinese Herbal ; therapeutic use ; Lipid Peroxidation ; drug effects ; Male ; Myocardial Infarction ; drug therapy ; metabolism ; pathology ; Myocardial Reperfusion Injury ; prevention & control ; Rats ; Rats, Sprague-Dawley

Recent studies have documented that Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) pathway can modulate the apoptotic program in a myocardial ischemia/reperfusion (I/R) model. To date, however, limited studies have examined the role of JAK3 on myocardial I/R injury. Here, we investigated the potential effects of pharmacological JAK3 inhibition with JANEX-1 in a myocardial I/R model. Mice were subjected to 45 min of ischemia followed by varying periods of reperfusion. JANEX-1 was injected 1 h before ischemia by intraperitoneal injection. Treatment with JANEX-1 significantly decreased plasma creatine kinase and lactate dehydrogenase activities, reduced infarct size, reversed I/R-induced functional deterioration of the myocardium and reduced myocardial apoptosis. Histological analysis revealed an increase in neutrophil and macrophage infiltration within the infarcted area, which was markedly reduced by JANEX-1 treatment. In parallel, in in vitro studies where neutrophils and macrophages were treated with JANEX-1 or isolated from JAK3 knockout mice, there was an impairment in the migration potential toward interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1), respectively. Of note, however, JANEX-1 did not affect the expression of IL-8 and MCP-1 in the myocardium. The pharmacological inhibition of JAK3 might represent an effective approach to reduce inflammation-mediated apoptotic damage initiated by myocardial I/R injury.
Animals ; Apoptosis/drug effects ; Cell Movement/drug effects ; Chemokines/pharmacology ; Heart Function Tests/drug effects ; Inflammation/pathology ; Janus Kinase 3/*antagonists & inhibitors/metabolism ; Macrophages/drug effects/metabolism/pathology ; Male ; Mice ; Mice, Inbred C57BL ; Myocardial Reperfusion Injury/drug therapy/*enzymology/physiopathology/*prevention & control ; Myocardium/enzymology/pathology ; Myocytes, Cardiac/drug effects/metabolism/pathology ; Neutrophils/drug effects/metabolism/pathology ; Quinazolines/pharmacology/therapeutic use

OBJECTIVEIn this study, we try to find the better protocol of limb ischemia postconditioning by observing different protective effects of limb ischemic postconditioning (different strength and time windows in rabbits).

METHODS42 healthy New Zealand rabbits were randomly divided into 7 groups (n = 6): Sham; Control (CON); Skeletal muscle postconditioning (SP); 6 min-delayed skeletal muscle postconditioning (6M-DSP); 1 min-delayed skeletal muscle postconditioning (1M-DSP); Strengthen skeletal muscle postconditioning (SSP); Weakened skeletal muscle postconditioning (WSP). Acute ischemia/reperfusion (I/R) model was induced by 45 minutes occlusion on left circumflex coronary artery (LCX) and 2 hours reperfusion in all anesthetized open-chest rabbits except the Sham. Limb ischemia was induced by external iliac arteries occlusion and reperfusion through artery clamps. The extent of myocardial infarction was assessed by triphenyltetrazolium (TTC) staining. Blood serum creatine kinase (CK) activity and lactate dehydrogenase (LDH) activity were measured at baseline,the end of ischemia, after 1 hour and 2 hours of reperfusion respectively.

RESULTSCompared with the CON, the weight ratio and area ratio of myocardial infarction size were significantly decreased by 49.97% and 43.78% in SP, by 42.32% and 42.68% in 1M-DSP, by 48.36% and 48.86% in SSP (P < 0.05). But there was no significant difference between SP and 1M-DSP and SSP (P > 0.05). Otherwise, compared with the CON, myocardial infarct size was not significantly reduced in 6M-DSP or WSP (P > 0.05). The change of CK was similar to the trend of myocardial infarct size.

CONCLUSIONThe limb ischemia strength of 5 mini/1 minR x 1 cycle could significantly reduce the myocardial ischemia/ reperfusion injury in rabbits, if it was achieved before myocardial reperfusion.

Animals ; Extremities ; blood supply ; Ischemic Postconditioning ; methods ; Male ; Muscle, Skeletal ; blood supply ; Myocardial Infarction ; pathology ; Myocardial Reperfusion Injury ; pathology ; prevention & control ; Myocardium ; metabolism ; Rabbits

BACKGROUNDInflammation is one of important mechanisms for myocardial ischemia reperfusion injury (IRI). Ischemia postconditioning (IPOC) can protect the heart against IRI by inhibiting inflammation, but its cardioprotection is weaker than that of ischemia preconditioning. Recently, the α7 subunit-containing nicotinic acetylcholine receptor (α7nAChR) agonist has shown anti-inflammatory effects in many diseases related to inflammation. This randomized controlled experiment was designed to evaluate whether combined postconditioning with IPOC and the α7nAChR agonist could produce an enhanced cardioprotection in a rat in vivo model of acute myocardial IRI.

METHODSFifty Sprague-Dawley rats were randomly divided into five equal groups: sham group, control group, IPOC group, α7nAChR agonist postconditioning group (APOC group) and combined postconditioning with IPOC and α7nAChR agonist group (combined group). Hemodynamic parameters were recorded during the periods of ischemia and reperfusion. Serum concentrations of troponin I (TnI), tumor necrosis factor α (TNF-α) and high-mobility group box 1 (HMGB-1) at 180 minutes after reperfusion were assayed in all groups. At the end of the experiment, the infarct size was assessed from excised hearts by Evans blue and triphenyl tetrazolium chloride staining.

RESULTSAs compared to the sham group, the infarct size in the other four groups was significantly increased, serum levels of TnI, TNF-α and HMGB1 in the control group and TNF-α, HMGB1 in the IPOC group were significantly increased. The infarct size and serum concentrations of TNF-α, HMGB1 and TnI in the IPOC, APOC and combined groups were significantly lower than those in the control group. As compared to the IPOC group, the infarct size in the combined group was significantly decreased, serum concentrations of TnI, TNF-α and HMGB1 in the APOC and combined groups were significantly reduced. Although the infarct size was significantly smaller in the combined group than in the APOC group, serum levels of TNF-α and HMGB1 were significantly higher in the combined group than in the APOC group.

CONCLUSIONSIn a rat in vivo model of acute myocardial IRI, combined postconditioning with IPOC and the α7nAChR agonist can produce enhanced protection against myocardial IRI by increasing the anti-inflammatory effect.

Animals ; Heart ; drug effects ; Ischemic Preconditioning, Myocardial ; methods ; Male ; Myocardial Reperfusion Injury ; prevention & control ; Myocardium ; pathology ; Nicotinic Agonists ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Receptors, Nicotinic ; metabolism ; Tumor Necrosis Factor-alpha ; blood ; alpha7 Nicotinic Acetylcholine Receptor

OBJECTIVETo investigate the effects of hydrogen sulfide preconditioning on myocardial ischemia reperfusion injury in rats.

METHODSSprague-Dawley male rats were divided into 4 groups with 10 in each group: in S group rats received sham operation; in IR group rats were given with NS (1.0 ml/kg iv) 24 h before ischemia; in H group rats were treated with NaHS (0.05 mg/kg iv) 24 h before ischemia; and in D group, NaHS-treated rats received 5-hydroxydecanoate (5-HD) 15 min before ischemia. Rats in IR group,H group and D group were subjected to ischemia by occlusion of coronary artery for 30 min followed by 2 h of reperfusion. At the end of the reperfusion,myocardial infarct size was measured. SAM-s was measured by Western blotting. Plasma SOD activity and MDA were determined at the end of reperfusion.

RESULTSThe infarct size was significantly lesser in H group (25.40 % ± 3.54%) than that in IR group (38.27% ±5.64%,P<0.05). The SAM-s protein expression in myocardium was significantly lower in H group than that in IR group. The plasma MDA content was significantly lower and SOD activity was higher in H group than those in IR group,but there was no difference between IR group and D group.

CONCLUSIONThe hydrogen sulfide preconditioning attenuates myocardial IR injury possibly through down-regulating SAM-s expression,reducing the production of oxygen free radicals and enhancing anti-oxidize effect in rats.

Animals ; Disease Models, Animal ; Hydrogen Sulfide ; pharmacology ; Ischemic Preconditioning, Myocardial ; Male ; Myocardial Reperfusion Injury ; metabolism ; pathology ; prevention & control ; Myocardium ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate whether inhaled sevoflurane is capable of producing delayed cardioprotection effect in rats and its underlying mechanisms.

METHODSMale Sprague-Dawley rats inhaled 1.0 minimum alveolar concentration (MAC) sevoflurane, 1.5 MAC sevoflurane,or O(2) for 1 h. After 24 h and 48 h the left coronary artery of rats was occluded for 30 min,followed by 120 min of reperfusion. Hemodynamics was continuously recorded and myocardial infarct size was determined by Evans blue and triphenyltetrazolium chloride staining. The expression of nitric oxide synthase (NOS) was assessed by immunoblotting.

RESULTS1.0 MAC sevoflurane and 1.5 MAC sevoflurane improved cardiac pump function after reperfusion and reduced myocardial infarct size with the increased iNOS expression (P<0.05). However,the expression of eNOS and p-eNOS was not affected (P>0.05). A selective iNOS inhibitor 1400 W abolished the cardioprotection effect induced by inhalation of 1.0 MAC sevoflurane for 24 h.

CONCLUSIONSevoflurane produces delayed cardioprotection through the up-regulation of iNOS expression.

Anesthetics, Inhalation ; pharmacology ; Animals ; Disease Models, Animal ; Ischemic Preconditioning, Myocardial ; Male ; Methyl Ethers ; pharmacology ; Myocardial Reperfusion Injury ; enzymology ; pathology ; prevention & control ; Myocardium ; enzymology ; pathology ; Nitric Oxide Synthase Type II ; metabolism ; Rats ; Rats, Sprague-Dawley ; Up-Regulation ; drug effects

OBJECTIVETo identify the underlying mechanisms of the protective effects of Dingxin Recipe (: , DXR), a Chinese compound prescription that has been used clinically in China for more than 20 years, on ischemia/reperfusion (I/R)-induced arrhythmias in rat model.

METHODSA total of 30 rats were randomly divided into three groups: sham group, I/R group, and DXR-pretreated I/R (DXR-I/R) group. Rats in the DXR-DXRI/R group were intragastrically administrated with DXR (12.5 g/kg per day) for consecutive 7 days, while rats I/in the sham and I/R groups were administrated with normal saline. Arrhythmias were introduced by I/R and electrocardiograms (ECG) were recorded. Two-dimensional (2-D) polyacrylamide gel electrophoresis and matrix-matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used to identify assisted differentially expressed proteins. Immunohistochemistry, real-time quantitative polymerase chain reaction (RQ-RQPCR), Western blot, and enzyme-linked immunosorbent assay (ELISA) were performed to analyze proteins PCR), obtained in the above experiments.

RESULTSDXR significantly reduced the incidence and mean duration of ventricular tachycardia and ventricular fibrillation and dramatically decreased the mortality, as well as arrhythmia score, compared with those of the I/R group. Among successfully identified proteins, prohibitin (PHB) and heart fatty acid binding protein (hFABP) were up-regulated in DXR-pretreated I/R rats compared with those of the I/R rats. In addition, compared with the I/R group, the level of glutathione (GSH) was elevated accompanied by reduced expressions of interleukin-6 (IL-6) and neutrophil infiltration in I/R rats with DXR pretreatment.

CONCLUSIONSDXR could alleviate I/R-induced arrhythmias, which might be related to increased expression of PHB. The enhanced expression of PHB prevented against the depletion of GSH and consequently inhibited apoptosis of cardiomyocytes. Furthermore, up-regulation of PHB might ameliorate I/R-induced cell death and leakage of hFABP by suppressing neutrophil infiltration and IL-6 expressions.

Animals ; Arrhythmias, Cardiac ; etiology ; prevention & control ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Electrophoresis, Gel, Two-Dimensional ; Fatty Acid Binding Protein 3 ; Fatty Acid-Binding Proteins ; metabolism ; Glutathione ; metabolism ; Heart Ventricles ; drug effects ; metabolism ; pathology ; Immunohistochemistry ; Inflammation ; complications ; metabolism ; pathology ; Interleukin-6 ; metabolism ; Male ; Myocardial Infarction ; complications ; drug therapy ; pathology ; Neutrophil Infiltration ; drug effects ; Peptide Mapping ; Proteomics ; Rats ; Rats, Wistar ; Reperfusion Injury ; complications ; Repressor Proteins ; metabolism ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Spectrophotometry ; Up-Regulation ; drug effects

OBJECTIVETo evaluate the anti-apoptotic effect of aldehyde dehydrogenase 2 (ALDH2) on myocardial ischemia/reperfusion (I/R) injury in diabetic rats.

METHODSNormal male SD rats were divided into normal, diabetes and ethanol (the agonist of ALDH2) + diabetes groups. In the latter two groups, diabetes was induced by an intraperitoneal injection of 55 mg/kg STZ. Four weeks after the modeling, myocardial I/R was mimicked ex vivo, and lactate dehydrogenase (LDH) content in the coronary flow was determined. The activities of caspase-3 and ALDH2 were evaluated, and the expressions of Bcl-2 and Bax mRNA in the left anterior myocardium were detected using RT-PCR.

RESULTSIn diabetic group, LDH release and caspase-3 activity were increased, while ALDH2 activity and Bcl-2/Bax mRNA expression were decreased as compared to those in normal control group. Compared with the diabetic group, ALDH2 agonist ethanol significantly reduced LDH release and caspase-3 activity, increased ALDH2 activity and Bcl-2/Bax mRNA expression.

CONCLUSIONIn diabetic rats, enhanced ALDH2 expression can offer mycardial protection possibly in relation to suppress cell apoptosis.

Aldehyde Dehydrogenase ; metabolism ; Aldehyde Dehydrogenase, Mitochondrial ; Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Diabetes Mellitus, Experimental ; complications ; enzymology ; Ethanol ; pharmacology ; Male ; Mitochondrial Proteins ; agonists ; metabolism ; Myocardial Ischemia ; enzymology ; etiology ; Myocardial Reperfusion Injury ; enzymology ; pathology ; prevention & control ; Myocardium ; enzymology ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; bcl-2-Associated X Protein ; metabolism