GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis in rats

Hydrogen sulfide （H2S） is a gasotransmitter that regulates cardiovascular functions. The present study aimed to determine the protective effect of slow-releasing H2S donor GYY4137 on myocardial ischemia and reperfusion （I/R） injury and to investigate the possible signaling mechanisms involved. Male Sprague-Dawley rats were treated with GYY4137 at 12.5 mg/（kg.day）, 25 mg/（kg.day） or 50 mg/（kg.day） intraperitoneally for 7 days. Then, rats were subjected to 30 minutes of left anterior descending coronary artery occlusion followed by reperfusion for 24 hours. We found that GYY4137 increased the cardiac ejection fraction and fractional shortening, reduced the ischemia area, alleviated histological injury and decreased plasma creatine kinase after myocardial I/R. Both H2S concentration in plasma and cystathionine-γ-lyase （CSE） activity in the myocardium were enhanced in the GYY4137 treated groups. GYY4137 also decreased malondialdehyde and myeloperoxidase levels in serum, attenuated superoxide anion level and suppressed phosphorylation of mitogen activated protein kinases in the myocardium after I/R. Meanwhile, GYY4137 increased the expression of Bcl-2 but decreased the expression of Bax, caspase-3 activity and apoptosis in the myocardium. The data suggest that GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis.

Microvessel changes in the gerbil hippocampus after cerebral ischemia and reperfusion by Buyang Huanwu decoction pretreatment

Buyang Huanwu decoction （BYHWD） is a classic recipe for the prevention and treatment of ischemic cerebrovascular disease. Gerbils were pretreated with BYHWD, and then subjected to cerebral ischemia and reperfusion. Microvascular changes were determined with laser Doppler monitoring, tannic acid-ferric chloride mordant, and electron microscopy. Results showed that BYHWD pretreatment could enhance the function of hippocampal microvessels, prevent injury, and increase microvasular density and microvasular area density. Thus, these results suggest that BYHWD pretreatment could prevent microvascular occlusion, enhance the capacity of microvascular reperfusion, increase cerebral blood flow, and inhibit neuronal damage, and may be an effective therapy against brain ischemic injury.

Expression of neurocan mRNA and ultrastructure of brain tissue after cerebral ischemia and reperfusion in stroke-prone renovascular hypertensive rats treated by electroacupuncture

We established a stroke-prone renovascular hypertensive rat model by bilateral constriction of the renal artery with sliver loop clips. After ten weeks, middle cerebral artery occlusion was induced for 2 hours. The rats then received electro-acupuncture at Baihui （DU 20） and Dazhui （DU 14） after onset of ischemia for 30 days. In situ hybridization study showed that electroacupuncture significantly reduced the number of neurocan mRNA-positive cells in the ischemic penumbra and hippocampal tissues of rats. Electron microscopy results demonstrated that the structure of neurons and blood vessels in the ischemic tissues were restored with electroacupuncture. Overall, these data suggest that electroacupuncture may protect neurons against ischemic reperfusion injury in stroke-prone renovascular hypertensive rats, which may be regulated by downregulation of expression of nerve inhibitory factor neurocan mRNA.

Effects of L-Tetrahydropalmatine on the Expressions of bcl-2 and bax in Rat after Acute Global Cerebral Ischemia and Reperfusion

To investigate the effects of L-Tetrahydropalmatine (L-THP) on the expressions of bcl-2, bax and neuronal apoptosis after cerebral ischemia and reperfusion, 60 Wistars rats were randomly divided into 3 groups: sham-operation group (group S, n = 20), ischemic-reperfusion group treated with saline (group I, n=20) and ischemia-reperfusion group treated with L-THP (group T, n=20) .The rat model of global cerebral ischemia and reperfusion was induced by Pulsinelli's four-vessel occlusion method. The expression of bcl-2 and bax mRNA was detected by in situ hybridization and reverse transcriptional polymerase chain reaction (RT-PCR). The number of apoptotic neurons was examined by terminal deoxynucleotidyl-transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) method. Compared with group S, the expression of bcl-2 and bax mRNA in group I was increased significantly (P<0.01), and the number of apoptotic neurons increased either (P< 0.01). After L-THP treatment, the expression of bcl-2 mRNA was up-regulated (P<0.01) and that of bax mRNA was down-regulated (P<0.01); the number of apoptotic neurons was decreased (P<0.01). Our results indicated that bcl-2 may suppress apoptosis and bax promote apoptosis after cerebral ischemia and reperfusion. L-THP could ameliorate cerebral ischemia and reperfusion damage by reducing the apoptosis through regulating bcl-2 and bax.

Expression of cyclin-dependent protein kinase 5 in the hippocampus of vascular dementia mice after cerebral ischemia and reperfusion

BACKGROUND： The p25-activated cyclin-dependent protein kinase 5 （Cdk5） may induce neuronal cell death and cause the development of dementia following cerebral ischemia and reperfusion. OBJECTIVE： To observe changes in the expression of Cdk5 and p25 in hippocampal tissue of vascular dementia mice at different time points following cerebral ischemia and reperfusion. DESIGN, TIME AND SETTING： A randomized, controlled animal experiment was performed in the clinical trial center of Hebei Provincial People＇s Hospital between September 2007 and October 2008. MATERIALS： Cdk5 rabbit anti-mouse polyclonal antibody, p35 rabbit anti-mouse polyclonal antibody, and β-actin mouse monoclonal antibody were purchased from Santa Cruz Biotechnology, Inc., USA; horseradish peroxidase-labeled goat anti-rabbit IgG and horseradish peroxidase-labeled goat anti-mice IgG were offered by Beijing Zhongshan Geldenbridye Biotechnology Co.,Ltd., China; the protein quantitative kit was produced by Applygen Gene Technology Corp., Beijing, China; cDNA reverse transcription and PCR amplification reagents were products of TianGen＆ Biotech （Beijing） Co.,Ltd., China. METHODS： One hundred and sixty male Kunming mice were randomly divided into two groups： a sham-operated group （n = 65） and a model group （n = 95）. Vascular dementia was induced with three periods of transient ischemia and reperfusion of the bilateral common carotid arteries. In the sham-operated group, the bilateral common carotid arteries were not blocked. MAIN OUTCOME MEASURES： Behavioral tests were done at four and six weeks post surgery. Pathological changes in the hippocampal CA1 region were observed with hematoxylin-eosin staining Cdk5 mRNA expression was examined by RT-PCR, and Western blots were used to evaluate Cdk5 and p25 expression. Learning and memory performance were assayed using the Morris water maze. RESULTS： Vascular dementia reduced learning and memory performance at 4 and 6 weeks post surgery. Vascular dementia also caused severe, time-dependent neuronal damage and death in the hippocampal CA1 region. Dementia induction also increased mRNA and protein expression of Cdk5 and p25 at both 4 and 6 weeks after surgery. CONCLUSION： Cdk5/p25 is involved in the development of vascular dementia in mice following cerebral ischemia and reperfusion.

Correlation between expression of two transforming growth factor-beta 1 receptors and microvascular density in a rat model of cerebral ischemia and reperfusion injury

The effects of transforming growth factor-β1 （TGF-β1） are currently controversial. Whether TGF-β1 promotes or inhibits revascularization under different conditions remains poorly understood. Based on previous studies, the current experiment established rat models of cerebral ischemia and reperfusion injury （IRI）, and demonstrated that pathological and functional damage was also increased after IRI. The most serious damage was observed at 3 days after reperfusion, at which time microvascular density fell to its lowest level. Soon afterwards, microvascular density increased, new collateral circulation was gradually established at 4 to 7 days after reperfusion, and pathological damage and neurological deficits were improved. TGF-β1, activin receptor-like kinase 5 （ALK5） mRNA and protein expression levels increased gradually over time. In contrast, ALK1 mRNA and protein expression decreased over the same period. A significant negative correlation was detected between microvascular density and expression of the ALK5 gene transcript. There was no correlation between microvascular density and ALK1 gene transcriptional expression following cerebral IRI in a rat model. These findings suggest that ALK5, rather than ALK1, is the critical receptor in the TGF-β1 signal pathways after cerebral IRI.

Argon: a novel therapeutic option to treat neuronal ischemia and reperfusion injuries?

Neuronal injury and neuroprotection：Ischemia and reperfusion injuries in neuronal cells such as acute ischemic stroke-represent the third leading cause of death in the world.Current therapeutic concepts mainly aim to re-establish cerebral blood flow within a time window of less than 3 hours with the goal of limiting secondary brain injury.

Intestinal ischemia and reperfusion induced second impairment of the rat heart

Objective: To study the changes of oxygen free radical, expression of apoptotic gene, ultrastructure of myocardial cell and second injury of the heart following the intestinal ischemia and reperfusion. Methods: Making the models of ischemia and reperfusion by clamping superior mesenteric artery, the concentration of NO and SOD in the blood was examined before clamping the artery and reperfusion for 0, 30, 60 min, 1, 3, and 7 d. The expression of Bax, Bal-2, and p53 in myocardial cell was studied by means of immunohistochemical SP method and the microstructure damage was observed under electron microscopy. Results: After clamping the superior mesenteric artery and reperfusion the concentration of NO increased continuously and reached a peak for reperfusion 7 d (P<0.01) but that of SOD decreased from 30 min to 7 d. The expression of Bax, p53 and Bcl-2 also increased obviously especially for reperfusion 30 min and 7 d following ischemia and reperfusion. After reperfusion for 30 min the positive cell rate of Bax, p53 and Bcl-2 was 53.6%, 45.9% and 67.9%, for reperfusion 7 d it was 52.4%, 43.4% and 31.9% respectively, but the positive cell rate of Bax and p53 was higher than that of Bcl-2. The result of electron microscopy observation showed mfofiliments breaked, dissolved and chromatin condensed. Conclusion: Intestinal ischemia and reperfusion of rat can induced the changes of oxygen free radical and the expression of apoptotic gene and second injury of myocardial cells.

Astragali and Angelica protect the kidney against ischemia and reperfusion injury and accelerate recovery

Objective To investigate the role of Astragali and Angelica (A&A) of Chinese herbs in acute renal ischemia/reperfusion injury, and the related intracellular signal transduction mechanism. Methods Acute ischemic renal injury in rats was induced by clamping in renal pedicel for 45 minutes. Rats in therapy group were given a single dose (2 ml/day) of A&A for 3 days before clamping, and then continued for another 3 days. Forty-five minutes after clamping and at different reperfusion time, serum creatinine (Scr) and renal pathological changes were taken and compared in both groups. The proliferating cell nuclear antigen (PCNA) positive cells were detected by immunohistochemistry. Extracelluar regulating kinase (ERK) and c-Jun N-terminal kinase (JNK) activity was assayed by specific substrate phosphorylation with immunoprecipitation. Results At the 24th hour of reperfusion, Scr was lower in A&A group than that in the control. Much less necrotic tubular cells， casts， and more PCNA-positive cells were found in A&A group. ERK activity decreased after clamping, and recovered at 5 minutes of reperfusion. There was no difference between the two groups. JNK activity did not change after ischemia, but increased at 5 minutes and peaked at 20 minutes of reperfusion. JNK activity was significantly higher in A&A group than that in the control group. Conclusion A&A protected kidney against ischemic insult and accelerated both functional and histological recovery after acute renal ischemia/reperfusion injury, which may associate with the change of JNK signaling pathway.

Effect of adrenomedullin on neuron apoptosis, infarction volume and expression of Egr-1 mRNA after focal ischemia-reperfusion in rats

Objective To observe the influence of adrenomedullin （ADM） on neuron apoptosis, infarction volume of brain, and the expression of early growth response 1 （Egr-1） mRNA in ischemia-reperfusion rats. Methods The arteria cerebri media was tied for 2 h to construct the ischemia model. Infarction volume was detected by triphenltetrazolium chloride （T＇I＇C） staining, neuronal apoptosis and necrosis was detected with terminal deoxynucleotidyl transferase nick labeling （TUNEL） method, and the Egr-1 mRNA expression was examined by in situ hybridization （ISH）. Results Infarction volume after ischemia-reperfusion is （269 ± 20） mm^3. Infarction volume after injection of ADM through different ways are femoral vein （239 ± 17） mm^3 （decreased by 11.2%）, arteria carotis （214 ± 14） mm^3 （by 20.4%） and lateral cerebral ventricle （209 ± 13） mm^3 （by 22.3%）, respectively. The results indicate that injecting ADM through arteria carotis and lateral cerebral ventricle is much more effective than it through femoral vein （P 〈 0.05）. The TUNEL-positive cells in cerebral cortex or hippocampus are few in the sham operation group, but much more in the ischemia-reperfusion group. After being supplied with ADM, especially through arteria carotis interna or lateral cerebral ventricle way, the TUNEL-positive cells decreased obviously. Expression of Egr- 1 mRNA was low in the cerebral cortex of the sham operation group rats, enhanced in the ischemia and reperfusion group rats, and enhanced markedly after treatment with ADM, especially through arteria carotis interna or lateral cerebral ventricle way （P 〈 0.01）. Conclusion Injection of ADM through different ways could alleviate neural dysfunction, decrease neuron apoptosis and brain infarction volume, and increase the expression of Egr- 1 mRNA.

Salvianolate Reduces Murine Myocardial Ischemia and Reperfusion Injury via ERK1/2 Signaling Pathways in vivo

Objective： To analyze the effects of salvianolate on myocardial infarction in a murine in vivo model of ischemia and reperfusion （I/R） injury. Metheds： Myocardial I/R injury model was constructed in mice by 30 min of coronary occlusion followed by 24 h of reperfusion and pretreated with salvianolate 30 min before I/R （SAL group）. The SAL group was compared with SHAM （no I/R and no salvianolate）, I/R （no salvianolate）, and ischemia preconditioning （IPC） groups. Furthermore, an ERK1/2 inhibitor PD98059 （1 mg/kg）, and a phosphatidylinositol-3-kinase （PI3-K） inhibitor, LY294002 （7.5 mg/kg）, were administered intraperitoneal injection （i.p） for 30 min prior to salvianolate, followed by I/R surgery in LY and PD groups. By using a double staining method, the ratio of the infarct size （IS） to left ventricle （LV） and of risk region （RR） to LV were compared among the groups. Correlations between IS and RR were analyzed. Western-blot was used to detect the extracellular signal-regulated kinase 1/2 （ERK1/2） and protein kinase B （AKT） phosphorylation changes. Results： There were no significant differences between RR to LV ratio among the SHAM, I/R, IPC and SAL groups （P〉0.05）. The SAL and IPC groups had IS of 26.1% ± 1.4% and 22.3% ±2.9% of RR, respectively, both of which were significantly smaller than the I/R group （38.5% ± 2.9% of RR, P〈0.05, P〈0.01, respectively）. Moreover, the phosphorylation of ERK1/2 was increased in SAL group （P〈0.05）, while AKT had no significant change. LY294002 further reduced IS, whereas the protective role of salvianolate could be attenuated by PD98059, which increased the IS. Additionally, the IS was not linearly related to the RR （r=0.23, 0.45, 0.62, 0.17, and 0.52 in the SHAM, I/R, SAL, LY and PD groups, respectively）. Conclusion： Salvianolate could reduce myocardial I/R injury in mice in vivo, which involves an ERK1/2 pathway, but not a PI3-K signaling pathway.

Protective Effects of Danlou Tablet (丹蒌片) against Murine Myocardial Ischemia and Reperfusion Injury In Vivo

Objective： To observe the in vivo effect of Danlou Tablet（丹蒌片,DLT） on myocardial ischemia and reperfusion（I/R） injury.Methods： DLT effects were evaluated in mouse heart preparation using 30-min coronary occlusion followed by 24-h reperfusion and compared among sham group（n=6）,I/R group（n=8）,IPC group（ischemia preconditioning,n=6） and DLT group（I/R with DLT pretreatment for 3 days,750 mg·kg^（-1）·day^（-1）,n=8）.The effects of DLT were characterized in infarction size（IS） compared with risk region（RR） and left ventricle using the Evans blue/triphenyltetrazolium chloride double dye staining method in vivo.Furthermore,the dose-dependent effect of DLT on I/R injury was evaluated by double staining method.Five different concentrations of DLT（0.625,1.25,2.5,5 and 10 g·kg^（-1）·day^（-1）） were chosen in this study,and dose-response curve of DLT was obtained on these data.Results： The ratio of IS to left ventricle was significantly smaller in the DLT and IPC groups than the I/R group（P〈0.05 or P〈0.01）,the ratio of IS to RR was also reduced in the DLT and IPC groups（P〈0.01）,while there were no differences in RR among the four groups（P〉0.05）.Experiments showed incidence of arrhythmias was reduced in the DLT group（P〈0.01）.Furthermore,DLT produced a dose-dependent inhibitory effect with a half maximal inhibitory concentration of 1.225 g·kg^（-1）·day^（-1）.Conclusions： Our research concluded that DLT was effective in reducing I/R injury in mice,and provided experimental supports for the clinical use of DLT.

ACIDIC FIBROBLAST GROWTH FACTOR REDUCES RAT SKELETAL MUSCLE DAMAGE CAUSED BY ISCHEMIA AND REPERFUSION

Acute interruption of arterial blood flow to the extremities is often associated with significant morbidity and mortality. Broad spectrum mitogenic and non mitogenic activities of FGFs inspired us to study its protecting effects on tissue injuries in ischemia reperfusion condition. We found that systemic administration of aFGF after reperfusion onset prevented severe skeletal muscle injuries. In rats treated with aKGF, the tissue edema was reduced significantly, the tissue viability was increased, and the muscle fibers contained more succinate dehydrogenase (SDH) and adenosine triphosphatasc (ATPase). The pathological results supported the concept of improved prevention with aFGF treatment. The possible tissue protection by aFGF may come from its ability to regulate the concentration of evtra- and intracellular calcium ion. Besides, it may moderate other Ca2+ dependent enzyme conversion processes. Also, it may take part in the vascular tone regulation under ischemia and reperfusion conditions. These results suggest further study of tissue ischemia prevention with FGF and its possible mechanisms in the future.

Cardioprotective effects of morphine on rat heart suffering from ischemia and reperfusion

Objective To investigate the cardioprotective effects of morphine on ischemic reperfused rat heart in vitro and its mechanism Methods The isolated rat heart was perfused in a Langendorff apparatus Infarct myocardium was determined by TTC Coronary flow (CF), heart rate (HR), left ventricular pressure (LVP), the first derivative of ventricular pressure (LVP/dtmax) and infarct size after ischemia and reperfusion in rat heart given 0.3 μmol/L morphine were observed The effects of naloxone and glibenclamide on the cardioprotection of morphine were also measured Results After ischemia and reperfusion, CF, HR, LVP and LVP/dtmax of isolated rat hearts decreased significantly ( P <0 01) After morphine preconditioning, HR, LVP and LVP/dtmax increased ( P <0 01) and infarct size was reduced significantly ( P <0 01), while no significant change in CF ( P >0 05) The cardioprotective effects of morphine were abolished by naloxone or glibenclamide completely Conclusions Morphine can reduce ischemia reperfusion injuries in isolated rat heart The cardioprotective effects of morphine are mediated by a local opioid receptor K ATP channel linked mechanism in rat hearts

Protective effects of combination of Xuesaitong and aspirin on cerebral ischemia and reperfusion injury in rats

Objective：To investigate the protective effects of the combination of Xuesaitong（XST）and aspirin on cerebral ischemia and reperfusion injury（CIRI）in rats,and further explore the underlying mechanisms.Methods：A total of 150 male Sprague-Dawley（SD）rats were randomly divided into five groups with 30rats in each group：sham group,middle cerebral artery occlusion/reperfusion（MCAO/R）model group,XST group,aspirin group,and XST＋aspirin group.Rats were pretreated with XST,aspirin,or XST＋aspirin for7 d.One hour after the last administration,a model of CIRI was induced by MCAO/R.Neurological deficits were assessed using Longa’s five-point scale.Cerebral edema was detected by the measurement of brain water content.The volume of cerebral infarction was determined by 2,3,5-triphenyltetrazolium chloride（TTC）staining.The activities of superoxide dismutase（SOD）,catalase（CAT）,and glutathione peroxidase（GSH-Px）,as well as levels of malonaldehyde（MDA）were detected by commercial kits.Enzyme-linked immunosorbent assay（ELISA）was used to determine the levels of interleukin-1（）,interleukin-4（IL-4）,interleukin-6（IL-6）,interleukin-10（IL-10）,tumor necrosis factor-alphamonocyte chemotactic protein 1（MCP-1）,and kynurenine in serum,cerebral cortex,and hippocampus of MCAO/R rats.The protein expression of nuclear factor erythroid 2-related factor（Nrf2）,heme oxygenase-1（HO-1）,I-kappa B alpha（IκBα）,and nuclear factor kappa B（B）/p65 in the cortex were analyzed by western blotting.Results：Treatment of XST,aspirin,and XST＋aspirin significantly alleviated the neurological deficits,cerebral edema,and cerebral infarct volume induced by MCAO/R.Treatment of XST,aspirin,and XST＋aspirin also reduced MDA,,MCP-1,and kynurenine levels,and increased SOD,CAT,GSH-Px,IL-4,and IL-10 levels in serum,cerebral cortex,and hippocampus of MCAO/R rats.Furthermore,treatment of XST,aspirin,and XST＋aspirin decreased the expression of nuclearB/p65 and increased the expression of IκBα,nuclear Nrf2,and HO-1.Importantly,the combination of XST and aspirin enhanced the protective effects of XST or aspirin treatment alone on CIRI in rats.Conclusion：The combination of XST and aspirin significantly inhibited oxidative stress and inflammation in serum,cerebral cortex,and hippocampus of MCAO/R rats.The combination of XST and aspirin exerted more protective effects than XST or aspirin treatment alone.The combination of XST and aspirin might provide the synergistic therapeutic effects on CIRI,and deserve further clinical investigation.

Expression of netrin-1 and its receptors, deleted in colorectal cancer and uncoordinated locomotion-5 homolog B, in rat brain following focal cerebral ischemia reperfusion injury

Netrin-1 is currently one of the most highly studied axon guidance factors. Netrin-1 is widely expressed in the embryonic central nervous system, and together with the deleted in colorectal cancer and uncoordinated locomotion-5 homolog B receptors, netrin-1 plays a guiding role in the construction of neural conduction pathways and the directional migration of neuronal cells. In this study, we established a rat middle cerebral artery ischemia reperfusion model using the intraluminal thread technique. Immunofluorescence microscopy showed that the expression of netrin-1 and deleted in colorectal cancer in the ischemic penumbra was upregulated at 1 day after reperfusion, reached a peak at 14 days, and decreased at 21 days. There was no obvious change in the expression of uncoordinated locomotion-5 homolog B during this time period. Double immunofluorescence labeling revealed that netrin-1 was expressed in neuronal cells and around small vessels, but not in astrocytes and microglia, while deleted in colorectal cancer was localized in the cell membranes and protrusions of neurons and astrocytes. Our experimental findings indicate that netrin-1 may be involved in post-ischemic repair and neuronal protection via deleted in colorectal cancer receptors.

INCREASED VULNERABILITY OF HYPERTROPHIED MYOCARDIUM TO ISCHEMIA AND REPERFUSION INJURY RELATION TO CARDIAC RENIN-ANGIOTENSIN SYSTEM

Hearts of pressure-overload hypertrophy show an increased activation of intracardiac renin-angiotensin system which may contribute to ischemia and reperfusion injury. The purpose of this study is to evaluate whether the hypertrophied myocardium is more vulnerable to ischemia and reperfusion injury and to find out its relation to the cardiac renin-angiotensin system. Hypertrophied rat hearts induced by abdominal aortic banding for 6 weeks were subjected to 2 hours of hypothermic ischemic arrest followed by 30 minutes of reperfusion, and their cardiac function recovery was compared with that of sham-operated normal control hearts. The cardiac renin activity and angiotensin II content before ischemia and after reperfusion were determined. It was found that both the pre-ischemic renin activity and angiotensin II level were higher in hypertrophied myocardium than those in the control: ischemia and reperfusion injury increased both renin activity and angiotensin II content in the two groups, but the renin activity and angiotensin II level were further elevated after reperfusion in the hypertrophied hearts than those in the control hearts. Meanwhile, the cardiac function recovery after 30 minutes reperfusion in the hypertrophied hearts was poorer than that in the control. Correlation analysis revealed that there was a negative correlation between the cardiac output recovery and the myocardial angiotensin II content (r=-0.841), P<0.001), It is concluded that ischemia and reperfusion injury can activate cardiac renin-angiotensin system in isolated rat heart, which may be responsible for the increased susceptibility of the hypertrophied myocardium to ischemia and reperfusion injury.

Influence of Brain-activating Acupuncture on Cerebral Histomorphology in Rats with Focal Cerebral Ischemia and Reperfusion

Objective： To investigate the pathological changes following the focal cerebral ischemia and reperfusion in rats and the effect of acupuncture on them. Methods： A model of ischemia and reperfusion was established by thread occlusion, and the brain activating acupuncture was applied, and then the morphological changes of the cerebral cortex on the ischemic side were observed under electron and light microscopes. Results： Cerebral ischemia and reperfusion could lead to the structural injury of neurons, gliacytes and capillary vessels in rat＇s brain, and acupuncture could improve the ultra-structural injury in the area around the cerebral ischemia. It was also found that acupuncture intervention at 3 hours following reperfusion was more ideal than that at any other time points. Conclusion： Acupuncture has a protective effect on the ultra-structural injury of neurons associated with focal cerebral ischemia and reperfusion in rats, and acupuncture given within 3 hours following reperfusion can produce a satisfactory effect.

EFFECTS OF ADENOSINE IN SIMULATED ISCHEMIA ANDREPERFUSION ON ISOLATED GUINEA-PIG VENTRICULAR MYOCYTES

Objective To investigate the effects of adenosine （Ado） on myocardiac electrophysiology in simu- lated ischemla and reperfusion in guinea-pig ventricular myocytes. Methods Electrical activity was recorded using standard intracellular microelectrode technique. Right ventricle was superfused with simulated ischemic Tyrode’s so- lution for 15 min, and reperfued with normal Tyrode’s solution for 30 min. Results The results showed Ado had no measurable effects on guinea-pig ventricular myocytes in normal Tyrode’s solution. In the presence of Ado, maximal diastolic potential tended to be more depolarized during ischemia, and action potential （AP） parameters were abbrevi- ated greatly in a concentration-dependent manner. Especially, the concentration of Ado 100 μmol·L-1 had significant effects on AP parameters in ischemic phase [APD30, APD50, and APD90 reduced by （86±8）% versus （65±6）%, （70 ±7）% versus （50±6）%, and （60±6）% versus （42±4）% for control after 15 min, P<0.O5]. During reperfu- sion, AP parameters did not completely return to initial values in presence of Ado. This study illustrated that Ado significantly decreased incidence of arrhythmias induced by ischemia and reperfusion (in presence of Ado 100 μmol· L-1, the incidence of DAD decreased by 17% versus 82% for control during reperfusion). Conclusion Ado has no significant effects on guinea-pig ventricle in normal conditions, abbreviates greatly AP parameters during ischemia with a concentration-dependent manner, and has marked antiarrhythmic effects in ischemia and reperfusion.

A New Method of Superoxide Free Radical Determination in Ischemia and Reperfusion Injury of Rat Liver

The present study was designed to utilize the chemiluminescence(CL)method for O2- analysis in ischemia and reperfusion of the whole rat liver. The results indicated that the O2- level was lower after 30 and 60 min ischemia. After 40 min reperfusion, the level of O2- increased obviously,reaching about 8. 3-fold (30min ischemia) and 9. 0-fold (60 min ischemia) (P<0.001,P<0.01) respectively.The results also show that Chinese Traditional Medicines ligustrazine and salvia compound can scavenge O2- effectively.