OBJECTIVETo study the protective effect of Shenfu (Chinese traditional medicine) injections on myocardial ischemia/reperfusion (I/R) injury in rabbits.

METHODSThirty rabbits were divided into three groups (n = 10) randomly: control group, myocardial ischemia/ reperfusion group (MI/RI) and Shenfu injections extract group, three groups of rabbits were fed respectively with standard diet. After giving medicine 10 minutes, the myocardial ischemia/reperfusion injury animal model was established by ligaturing rabbits left ventricutar branch of coronary artery, and observing the changes of enzyme/hemodynamics during myocardial ischemia/reperfusion.

RESULTSIn model group myocardial function of shrink went down, the amount of malondialdehyde (MDA) was higher, the activity of superoxide dismutase (SOD), glutathine peroxidease (GSH-Px), Na(+) -K(+) -ATP and Ca(2+) -ATP were lower, lactic dehydrogenase (LDH) and creatine kinase(CK) were released compared with those in model group. Shenfu injections could recover left ventricular systolic pressure (LVSP) and +/- dp/dt(max), decrease left ventricular end-diastolic pressure(LVEDP), inhibit the increasing of MDA, LDH and CK, and increase the activaty of SOD, GSH-PX, Na(+) -K(+) -ATP and Ca(2+) -ATP.

CONCLUSIONShenfu injections can obviously protect myocardial ischemia/reperfusion injury.

Animals ; Calcium-Transporting ATPases ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Glutathione Peroxidase ; metabolism ; Hemodynamics ; drug effects ; Male ; Myocardial Ischemia ; physiopathology ; Myocardial Reperfusion Injury ; prevention & control ; Myocardium ; enzymology ; Rabbits ; Random Allocation ; Sodium-Potassium-Exchanging ATPase ; metabolism ; Superoxide Dismutase ; metabolism

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

Akt/protein kinase B is a well-known cell survival factor and activated by many stimuli including mechanical stretching. Therefore, we evaluated the cardioprotective effect of a brief mechanical stretching of rat hearts and determined whether activation of Akt through phosphatidylinositol 3-kinase (PI3K) is involved in stretch-induced cardioprotection (SIC). Stretch preconditioning reduced infarct size and improved post-ischemic cardiac function compared to the control group. Phosphorylation of Akt and its downstream substrate, GSK-3beta, was increased by mechanical stretching and completely blocked by wortmannin, a PI3K inhibitor. Treatment with lithium or SB216763 (GSK-3beta inhibitors) before ischemia induction mimicked the protective effects of SIC on rat heart. Gadolinium (Gd3+), a blocker of stretch-activated ion channels (SACs), inhibited the stretch-induced phosphorylation of Akt and GSK-3beta. Furthermore, SIC was abrogated by wortmannin and Gd3+. In vivo stretching induced by an aorto-caval shunt increased Akt phosphorylation and reduced myocardial infarction; these effects were diminished by wortmannin and Gd3+ pretreatment. Our results showed that mechanical stretching can provide cardioprotection against ischemia-reperfusion injury. Additionally, the activation of Akt, which might be regulated by SACs and the PI3K pathway, plays an important role in SIC.
Androstadienes/pharmacology ; Animals ; Gadolinium/pharmacology ; Glycogen Synthase Kinase 3/*metabolism ; Indoles/pharmacology ; *Ischemic Preconditioning, Myocardial ; Lithium/pharmacology ; Male ; Maleimides/pharmacology ; Myocardial Reperfusion Injury/enzymology/physiopathology/*prevention & control ; Phosphatidylinositol 3-Kinase/*antagonists & inhibitors/metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt/*metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Specific Pathogen-Free Organisms

BACKGROUNDThe traditional Chinese medicine Tongxinluo can protect myocardium against ischaemia/reperfusion injury, but the mechanism of its action is not well documented. We examined the involvement of nitric oxide in the protective role of Tongxinluo.

METHODSMiniswine were randomized to four groups of seven: sham, control, Tongxinluo and Tongxinluo coadministration with a nitric oxide synthase inhibitor N(omega)-nitro-L-arginine (L-NNA, 10 mg/kg i.v.). Three hours after administration of Tongxinluo, the animals were anaesthetised and the left anterior descending coronary artery ligated and maintained in situ for 90 minutes followed by 3 hours of reperfusion before death. Area of no reflow and necrosis and risk region were determined pathologically by planimetry. The degree of neutrophil accumulation in myocardium was obtained by measuring myeloperoxidase activity and histological analysis. Myocardial endothelial nitric oxide synthase activity and vascular endothelial cadherin content were measured by colorimetric method and immunoblotting analysis respectively.

RESULTSTongxinluo significantly increased the local blood flow and limited the infarct and size of no reflow. Tongxinluo also attenuated myeloperoxidase activity and neutrophil accumulation in histological sections and maintained the level of vascular endothelial cadherin and endothelial nitric oxide synthase activity in the reflow region when compared with control group. The protection of Tongxinluo was counteracted by coadministration with L-NNA.

CONCLUSIONSTongxinluo may limit myocardial ischaemia and protect the heart against reperfusion injury. Tongxinluo regulates synthesis of nitric oxide by altering activity of endothelial nitric oxide synthase.

Animals ; Antigens, CD ; analysis ; Blood Pressure ; drug effects ; Cadherins ; analysis ; Drugs, Chinese Herbal ; therapeutic use ; Heart Rate ; drug effects ; Microscopy, Fluorescence ; Myocardial Infarction ; drug therapy ; physiopathology ; Myocardial Reperfusion Injury ; prevention & control ; Myocardium ; enzymology ; pathology ; Neutrophil Infiltration ; Nitric Oxide ; physiology ; Nitric Oxide Synthase ; metabolism ; Peroxidase ; metabolism ; Swine ; Swine, Miniature

OBJECTIVETo observe the effect of pioglitazone on hypoxia/reoxygenation injury and the expression of protein kinase C (PKC) in neonatal rat cardiomyocytes.

METHODSNeonatal Sprague-Dawley rat cardiomyocytes in primary culture were treated with pioglitazone or GW9662 for 24 h prior to hypoxia/reoxygenation injury. Cardiomyocyte apoptosis was evaluated with Hoechst33258 staining and the expression of PKC was detected using Western blotting.

RESULTSIn the early stage of hypoxia/reoxygenation injury, the apoptosis rates of the cardiomyocytes increased significantly from (0.20∓0.03)% of the control level to (12.22∓1.45)% (P<0.05). Pretreatment with pioglitazone significantly lowered the apoptosis rate of the cardiomyocytes with hypoxia/reoxygenation injury to (8.32∓0.89)%, and this effect was antagonized by GW9662, a specific blocker of peroxisome proliferators activated receptors γ (PPARγ). Pioglitazone did not cause increased expression of PKC in the cardiomyocytes.

CONCLUSIONPioglitazone can ameliorate neonatal rat cardiomyocyte injury induced by hypoxia/reoxygenation partially by activating PPARγ and does not increase the expression of PKC in the cells.

Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Cell Hypoxia ; physiology ; Female ; Ischemic Preconditioning, Myocardial ; methods ; Male ; Myocardial Reperfusion Injury ; physiopathology ; prevention & control ; Myocytes, Cardiac ; enzymology ; pathology ; PPAR gamma ; metabolism ; Potassium Channels ; metabolism ; Primary Cell Culture ; Protein Kinase C ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Thiazolidinediones ; pharmacology