The protective effects of Astragaloside Ⅳ on diastolic function of rat thoracic aortic rings impaired by microvesicles / 中国应用生理学杂志

OBJECTIVES@#To investigate the effects of Astragaloside IV (AST) on diastolic function of rat thoracic aorta rings which was injured by microvesicles derived from hypoxia/reoxygenation (H/R)-treated human umbilical vein endothelial cells (HUVECs), and the mechanism of AST.@*METHODS@#H/R-induced endothelial microvesicles (H/R-EMVs) were generated from cultured HUVECs under the condition of hypoxia for 12 hour/Reoxygenation for 4 hour, H/R-EMVs were stored in D-Hank's solution. Male Wistar rats were underwent thoracotomy, the thoracic aorta with intact endothelium were carefully removed and cut into 3~4 mm rings. The experiment was divided into six groups. H/R-EMVs group:thoracic aortic rings of rats were incubated in culture medium and treated with H/R-EMVs in a final concentration of 10g/ml; different doses of AST groups:thoracic aortic rings of rats were treated with 10, 20, 40, 60 mg/L AST co-incubated with 10g/ml H/R-EMVs respectively; control group were treated with the same volume of D-Hank's solution. Duration of incubation was 4 h, each group was tested in five replicate aortic rings. Effects of AST on endothelium-dependent relaxation were detected. The production of nitric oxide (NO) and the level of endothelial NO synthase (eNOS), phosphorylated eNOS (p-eNOS, Ser-1177), serine/threonine kinase (Akt), phosphorylated Akt (p-Akt, Ser-473), extracellular regulated protein kinases (ERK1/2) and phosphorylated ERK1/2 (p-ERK1/2, Thr202/Tyr204) of rat thoracic aortic rings were detected.@*RESULTS@#Teng/ml H/R-EMVs could impaire the relaxation of rat thoracic aortic rings significantly (<0.01). Compared with H/R-EMVs group, relaxation of rat thoracic aortic rings was increased by 20, 40 and 60 mg/L AST in a concentration-dependent manner (<0.01), the level of NO production was also enhanced (<0.05, <0.01). The level of t-eNOS, t-Akt and ERK1/2 was not changed, but the level of p-eNOS, p-Akt and p-ERK1/2 increased by the treatment with AST (<0.01).@*CONCLUSIONS@#AST could effectively ameliorate endotheliumdependent relaxation of rat thoracic aortic rings impaired by H/R-EMVs in a concentration-dependent manner, the mechanism might involve the increase in production of NO, and the protein level of p-eNOS, p-Akt and p-ERK1/2.

Flow cytometric analysis of circulating microvesicles derived from myocardial Ischemic preconditioning and cardioprotection of Ischemia/reperfusion Injury in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To establish a flow cytometric method to detect the alteration of phenotypes and concentration of circulating microvesicles (MVs) from myocardial ischemic preconditioning (IPC) treated rats (IPC-MVs), and to investigate the effects of IPC-MVs on ischemia/reperfusion (I/R) injury in rats.</p><p><b>METHODS</b>Myocardial IPC was elicited by three.cycles of 5-min ischemia and 5-min reperfusion of the left anterior descending (LAD) coronary artery. Platelet-free plasma (PFP) was isolated through two steps of centrifugation at room temperature from the peripheral blood, and IPC-MVs were isolated by ultracentrifugation from PFR PFP was incubated with anti-CD61, anti-CD144, anti-CD45 and anti-Erythroid Cells, and added 1, 2 µm latex beads to calibrate and absolutely count by flow cytometry. For functional research, I/R injury was induced by 30-min ischemia and 120-min reperfusion of LAD. IPC-MVs 7 mg/kg were infused via the femoral vein in myocardial I/R injured rats. Mean arterial blood pressure (MAP), heart rate (HR) and ST-segment of electro-cardiogram (ECG) were monitored throughout the experiment. Changes of myocardial morphology were observed after hematoxylin-eosin (HE) staining. The activity of plasma lactate dehydrogenase (LDH) was tested by Microplate Reader. Myocardial infarct size was measured by TTC staining.</p><p><b>RESULTS</b>Total IPC-MVs and different phenotypes, including platelet-derived MVs (PMVs), endothelial cell-derived MVs (EMVs), leucocyte-derived MVs (LMVs) and erythrocyte-derived MVs (RMVs) were all isolated which were identified membrane vesicles (<1 Vm) with corresponding antibody positive. The numbers of PMVs, EMVs and RMVs were significantly increased in circulation of IPC treated rats (P<0.05, respectively). In addition, at the end of 120-min reperfusion in I/R injured rats, IPC-MVs markedly increased HR (P<0.01), decreased ST-segment and LDH activity (P < 0.05, P < 0.01). The damage of myocardium was obviously alleviated and myocardial infarct size was significantly lowered after IPC-MVs treatment (P < 0.01).</p><p><b>CONCLUSION</b>The method of flow cytometry was successfully established to detect the phenotypes and concentration alteration of IPC-MVs, including PMVs, EMVs, LMVs and RMVs. Furthermore, circulating IPC-MVs protected myocardium against I/R injury in rats.</p>

Microvesicles derived from hypoxia/reoxygenation-treated human umbilical vein endothelial cells impair relaxation of rat thoracic aortic rings / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effects of microvesicles (MVs) derived from hypoxia/reoxygenation (H/R)-treated human umbilical vein endothelial cells (HUVECs) on endothelium-dependent relaxation of rat thoracic aortic rings.</p><p><b>METHODS</b>H/R injury model was established to induce HUVECs to release H/R-EMVs. H/R-EMVs from HUVECs were isolated by ultracentrifugation from the conditioned culture medium. H/R-EMVs were characterized using 1 μm latex beads and anti-PE-CD144 by flow cytometry. Thoracic aortic rings of rats were incubated with 2.5, 5, 10, 20 μg/ml H/R-EMVs derived from H/R-treated HUVECs for 4 hours, and their endothelium-dependent relaxation in response to acetylcholine (ACh) or endothelium-independent relaxation in response to sodium nitroprusside (SNP) was recorded in vitro. The nitric oxide (NO) production of ACh-treated thoracic aortic rings of rats was measured using Griess reagent. The expression of endothelial NO synthase (eNOS) and phosphorylated eNOS (p-eNOS, Ser-1177) in the thoracic aortic rings of rats was detected by Western blotting. Furthermore, the levels of SOD and MDA in H/R-EMVs-treated thoracic aortic rings of rats were measured using SOD and MDA kit.</p><p><b>RESULTS</b>H/R-EMVs were induced by H/R-treated HUVECs and isolated by ultracentrifugation. The membrane vesicles (< 1 μm) induced by H/R were CD144 positive. ACh-induced relaxation and NO production of rat thoracic aortic rings were impaired by H/R-EMVs treatment in a concentration-dependent manner (P < 0.05, P < 0.01). The expression of total eNOS (t-eNOS) was not affected by H/R-EMVs. However, the expression of p-eNOS decreased after treated with H/R-EMVs. The activity of SOD decreased and the level of MDA increased in H/R-EMVs treated rat thoracic aortic rings (P < 0.01).</p><p><b>CONCLUSION</b>ACh induced endothelium-dependent relaxation of thoracic aortic rings of rats was impaired by H/R-EMVs in a concentration-dependent manner. The mechanisms included a decrease in NO production, p-eNOS expression and an increase in oxidative stress.</p>

Effects of endothelial microvesicles induced by A23187 on H9c2 cardiomyocytes / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effects of endothelial microvesicles (EMVs) induced by calcium ionophore A23187 on H9c2 cardiomyocytes.</p><p><b>METHODS</b>Human umbilical vein endothelial cells (HUVECs) were treated with 10 micromol/L A23187 for 30 min. EMVs from HUVECs were isolated by ultracentrifugation from the conditioned culture medium. EMVs were characterized using 1 and 2 microm latex beads and anti-PE-CD144 antibody by flow cytometry. For functional research, EMVs at different concentrations were cocultured with H9c2 cardiomyocytes for 6 h. Cell viability of H9c2 cells and the activity of LDH leaked from H9c2 cells were tested by colorimetry. Moreover, apoptosis of H9c2 cells was observed through Hoechst 33258 staining and tested by FITC-Annexin V/PI double staining.</p><p><b>RESULTS</b>EMVs were induced by A23187 on HUVECs, and isolated by ultracentrifugation. We identified the membrane vesicles (< 1 microm) induced by A23187 were CD144 positive. In addition, the EMVs could significantly reduce the viability of H9c2 cells, and increase LDH leakage from H9c2 cells in a dose dependent manner (P < 0.05). Condensed nuclei could be observed with the increasing concentrations of EMVs through Hoechst 33258 staining. Furthermore, increased apoptosis rates of H9c2 cells could be assessed through FITC-Annexin V/PI double staining by flow cytometry.</p><p><b>CONCLUSION</b>Microvesicles could be released from HUVECs after induced by A23187 through calcium influx, and these EMVs exerted a pro-apoptotic effect on H9c2 cells by induction of apoptosis.</p>

Effect of ERK1/2 signaling pathway on astragaloside IV protects H9c2 cells against H2O2-induced oxidative injury / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate whether Astragaloside IV(AST) protects H9c2 cells against H2O2-induced oxidative injury partly through ERK1/2 signaling pathway.</p><p><b>METHODS</b>H9c2 cells oxidative injury was induced by 200 tmol/L H2O2 for 6 hours to establish the H2O2-induced injury model of H9c2 cells. The viability of H9c2 cells was detected using MTf method. Activity of lactate dehydrogenase(LDH), total-superoxide dismutase (T-SOD), manganese-superoxide dismutase (Mn-SOD) and content of MDA (malondialdehyde) in the culture medium were detected using colorimetric method. Western blot was performed to exam expression of p-ERK1/2 and ERK1/2 in H9c2 cells respectively.</p><p><b>RESULTS</b>Under 200 micromol/L H2O2 treatment for 6 hours, the vaibility of H9c2 cells was suitable for the following study. Compared with H2O2 group, the cell viability was increased significantly in AST10 + H2O2 and AST2O + H2O2 groups (P < 0.01). The activity of LDH in the culture medium was decreased significantly (P < 0.01). The activity of T-SOD and Mn-SOD was increased significantly (P < 0.01), the content of MDA was decreased significantly (P < 0.01). Treated with 10 mg/L or 20 mg/L of AST, expression of p-ERK1/2 in H9c2 cells injured from H2O2 was increased significantly (P < 0.01), when PD98059 (inhibitor of ERK1/2) was added, the effects of AST were cancelled.</p><p><b>CONCLUSION</b>AST protects H9c2 cells against H2O2-induced oxidative injury partly through ERK1/2 signaling pathway.</p>

Cardioprotection of ramipril and BQ-123 against myocardial ischemia/reperfusion injury in vivo in rats / 中国应用生理学杂志

<p><b>AIM</b>To study the protective effects of ramipril in combination with BQ-123 on myocardial ischemia/reperfusion (I/R) injury in vivo in anesthetized rats.</p><p><b>METHODS</b>Healthy male Wistar rats were divided into 5 groups randomly and subjected to 30 min of myocardial ischemia followed by 120 min reperfusion. Ramipril, BQ-123 and their combination were given to rats respectively. To observe the protection of their combination against myocardial I/R injury. HR, MAP and the change of ST-segment were observed. Ventricular arrthymias were monitored. The activity of creatine kinase (CK) and lactate dehydrogenase (LDH) in plasma, the infarct size and morphologic change were examined.</p><p><b>RESULTS</b>Compared with I/R group, the elevation of ST-segment was decreased. Onsets of VPC and VT were delayed, durations of VPC and VT were shortened, especially their combination. Incidences of VPC, VT and VF were decreased. Activity of plasma CK and LDH was decreased, especially their combination. IS, IS/AAR and the morphology of myocardium were improved, especially their combination.</p><p><b>CONCLUSION</b>Ramipril, BQ-123 and combined using these two agents protected myocardium from I/R injury in vivo. The protective effects on delaying onset of VA, shortening duration of VA, decreasing the activities of CK and LDH, decreasing infrarct size and improving morphology of myocardium were better than using ramipril and BQ-123 alone.</p>

Study on ultrastructure of cardioprotection of ramipril against ischemia/reperfusion injury in diabetic rats / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of ramipril on myocardial ischemia/reperfusion injury in diabetic rats, and to explore its mechanism according to the observation on myocardial ultrastructure.</p><p><b>METHODS</b>Streptozotocin induced diabetic rats were divided randomly into three groups (n = 16): ischemia/reperfusion (I/R), ischemic preconditioning (IPC) and ramipril (RAM) group. Rats in RAM group were administered by RAM(1 mg x kg(-1) x d(-1)) orally for 4 weeks, the others were administered by normal saline. Then all rats were subjected to myocardial ischemia/ reperfusion injury. Rats in IPC group were preconditioned before ischemia. The ECG and the infarct size were examined. The changes of myocardial morphology were examined by light and electron microscopes.</p><p><b>RESULTS</b>Compared with I/R group, the elevation of ST segment and the incidence of ventricular tachycardia and ventricular fibrillation during ischemia were significantly decreased, the infarct size at the end of reperfusion was remarkably reduced, the myocardial morphology were significantly improved, special structure of myofilaments and mitochondria remained clearly, blood vessels were unobstructed, injury of endothelium were decreased in PC and RAM groups.</p><p><b>CONCLUSION</b>Ramipril administered for 4 weeks induces myocardial protection in diabetic rats, which is similar to that of IPC. The mechanism may be involved in protection of cardiocytes and mitochondria, and improvement of endothelial function.</p>

Effects of noninvasive limb ischemic preconditioning on anti-stress ability in mice / 中国应用生理学杂志

<p><b>AIM</b>To explore the effects of noninvasive limb ischemic preconditioning on the anti-stress ability in mice.</p><p><b>METHODS</b>Mice were divided into: normal group, control group, preconditioning group and drug group. Hypoxia tolerance test, swimming with weight loading, cold tolerance test and thermostable test were performed, and tolerance time in all the stringent state were observed. SOD activity of serum in hypoxia tolerance test and lactic acid of serum in swimming with weight loading test were determined.</p><p><b>RESULTS</b>The time of hypoxia tolerance in preconditioning group was markedly increased, and SOD activity of preconditioning group mice was significantly higher than those of control group, while they were both shorter than drug group. The average time of swimming in preconditioning group was markedly increased and the level of increasing the swimming time of preconditioning was the same as caffeine. Preconditioning could increase the survival time on high temperature markedly, and there was no significantly difference in the level of increasing the survival time between preconditioning group and chlorpromazine group. Preconditioning could increase the time of cold tolerance markedly compared with normal group.</p><p><b>CONCLUSION</b>Noninvasive limb ischemic preconditioning can improve the ability of anti-hypoxia, anti-fatigue, thermoresistance and cold-resistance in mice.</p>

Expression and significance of DNA topoisomerase I (topo I) in small cell lung cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the expression and its significance of DNA topoisomerase I (Topo I) in small cell lung cancer (SCLC).</p><p><b>METHODS</b>Topo I expression was detected by immunohistochemical S-P technique on 50 cases of SCLC and 12 cases of normal lung tissues.</p><p><b>RESULTS</b>The total positive rate of Topo I in normal lung tissue was 25.0% (3/12) and 78.0% (39/50) in SCLC. The expression of Topo I does not correlate with age, gender, smoking, tumor size and tumor site (P > 0.05), but significantly correlated with lymph node metastasis and clinical stage (P <0.05).</p><p><b>CONCLUSION</b>High Topo I expression is a rationale indication of Topo I inhibitor treatment of malignancies. It should be possible to predict anti-tumor drug sensitivity by assessment of Topo I expression and help to improve the therapeutic efficacy for cancer patients.</p>

A new vomiting animal model--mink / 药学学报

<p><b>AIM</b>To establish a new, reliable vomiting model in minks.</p><p><b>METHODS</b>Adult male minks (Mustela vison) were randomly divided into groups (n = 6). Cisplatin, apomorphine, copper sulfate and X-radiation were used to establish vomiting model. Retching and vomiting were observed after the vomiting models were given anti-vomiting agents. After the behavioral experiment, assay of 5-HT in the ileum was performed by immunohistologic method.</p><p><b>RESULTS</b>Cisplatin 7.5 mg.kg-1 i.p., apomorphine 1.6 mg.kg-1 s.c. and copper sulfate 40 mg.kg-1 ig were shown to evoke vomiting. Retching and vomiting were significantly inhibited in ondansetron and metoclopramide pretreated minks (P < 0.05, P < 0.01).</p><p><b>CONCLUSION</b>As a new vomiting model, minks may be of great value in studying vomiting mechanism and screening new antiemetic drugs.</p>