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Objective@#To investigate the early intervention effects of metoprolol on connexin 43(Cx43) and phosphorylated Cx43 (p-Cx43) expression in rabbits with post myocardial infarction.@*Methods@#A total of 24 adult male New Zealand white rabbits were divided into sham group (n=6), early treatment group(n=6), routine treatment group(n=6), and myocardial infarction group(n=6) with a randomized block design blocked by weight. Myocardial infarction was induced by left anterior descending coronary artery (LAD) ligation. Rabbits in sham group received similar surgical procedure without LAD ligation. Metoprolol (12.5 mg/kg dissolved in 2 ml distilled water) was applied to rabbits in early treatment group and routine treatment group per gavage immediately after recovery from anesthesia and at 24 hours after myocardial infarction, respectively, then treated daily for 40 days. Rabbits in sham group and myocardial infarction group received 2 ml distilled water per gavage daily for 40 days. Plasma lactate dehydrogenase (LDH) and creatine kinase (CK) level were detected by automatic biochemistry analyzer after 6 hours in all rabbits. Ventricular fibrillation threshold (VFT) was measured in vivo by bipolar pacing electrodes at 40 days. Cx43 and p-Cx43 distribution in ventricular tissue was detected by immunofluorescence analyses. Cx43 and p-Cx43 protein level in ventricular tissue was determined by Western blot.@*Results@#(1) Plasma LDH ((851.7±85.9)U/L vs. (332.3±39.6)U/L, P<0.01) and CK ((1 192.7±105.3)U/L vs. (462.3±65.6)U/L, P<0.01) were significantly higher in myocardial infarction group than in sham group (both P<0.01). (2) VFT was significantly lower in myocardial infarction group than that in sham group ((470.0±91.0) beats per minute vs. (683.3±60.9) beats per minute, P<0.05), and VFT was significantly higher in early treatment group ((633.3±43.2) beats per minute) and routine treatment group ((645.0±30.8) beats per minute) than in the myocardial infarction group (both P<0.05). (3) Immunofluorescence analyses showed that Cx43 was mainly localized in the intercalated disk, which was perpendicular to the cell long axis with linear arrangement, and less lateral distribution in sham group, early treatment group and routine treatment group, which was significantly different as the case in the myocardial infarction group. The expression of p-Cx43 in myocardial infarction group was less than in sham group, which was significantly upregulated in in early treatment group and routine treatment group when compared with myocardial infarction group, and expression of p-Cx43 was significantly higher in early treatment group than in routine treatment group. (4)The p-Cx43/Cx43 ratio of protein was significantly lower in myocardial infarction group than in sham group (0.165±0.011 vs. 0.363±0.046, P<0.05), and significantly higher in early treatment group (0.720±0.063) and routine treatment group (0.364±0.030) than in myocardial infarction group (both P<0.05), and this ratio was significantly higher in early treatment group than in routine treatment group (P<0.05).@*Conclusion@#Metoprolol treatment, especially the early metoprolol treatment (within 24 hours after LAD ligation), could significantly improve VFT by ameliorating the distribution and dephosphorylation of myocardial Cx43 in rabbits with experimental myocardial infarction.
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Objective The hsa-miR-106b-25 gene cluster is involved in various biological processes of carcinoma .This study aims at a prediction and function analysis of the hsa-miR-106b-25 gene cluster, miR-106b, miR-93, and miR-25, so as to provide some evidence for further studies on the functions of the three miRNAs and the mechanisms of their interaction . Methods We obtained the sequences of miR-106b, miR-93, and miR-25 from the miRBase, predicted their target genes with TargetScan , PicTar, and miRanda, and used 3 or more experimentally verified target genes from the miRTarbase as the gene set for further bioinformatic analysis .We predic-ted the biological processes of the target genes by GeneOntology analysis and enriched KEGG ( Kyoto Encyclopedia of Genes and Genomes) by pathway analysis, produced protein-protein interaction ( PPI) networks with STRING . Results The target genes of the miR-106b-25 gene cluster were significantly enriched in such biological processes as the regulation of macromolecule metabolism , regulation of metabolic process , and cell cycle process , while the KEGG pathway mainly in glioma, melanoma, prostate cancer , and gallbladder carcino-ma.The proteins encoded by the targeted genes of showed complicated interactions , and those encoded by the KAT2B, PTEN, TP53, CDH1, MDM2, E2F1, RB1, and SMAD7 plaid a core role in the interac-tion network. Conc lusoi n MiRNAs of the miR-106b-25 gene cluster regulate the downstream target proteins involved in tumorigenesis by participating in the cell cycle and cancer signaling pathway .
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Objective To synthetically evaluate the relationship between miR-31 and the prognosis of carcinoma and to investi-gate its related mechanism.Methods The correlative literatures of tumor prognosis were retrieved from the electronic databases PubMed,EMBASE and ISI Web of Science.The pooled hazard ratios (HRs)and 95% confidence interval(95%CI )were extracted. The prognostic data were performed the synthesis analysis.Results A total of 7 trials conformed to the inclusion criteria including accumulated 2 012 cases of carcinoma.Meta-analysis revealed that the decrease of miR-31 expression in the tumor patients had the poor prognosis (HR=0.784,95%CI :0.630-0.974);in the subgroup analysis,the synthesis results adopting the multivariable a-nalysis and China subjects were 3.512 (95%CI :1.797-6.865)and 1.574 (95%CI :1.062-2.333),which indicating that the in-crease of miR-31 expression predicted the poor prognosis;miR-31 had no statistical significance in the digestive system (P >0.05). Conclusion The prognostic role of miR-31 may possess the histological and regional specificity and has the potential as a novel marker.
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Objective To investigate the effect of astaxanthin( ASX)on endothelial progenitor cells( EPCs)injury induced by oxidative stress in vitro and to explore its underlying mechanism. Methods Cultured EPCs isolated from peripheral blood were randomly divided into 5 groups:normal control,model group[ tert-butyl hydroperoxide( tBHP)100μmol·L-1 ],and ASX+tBHPgroups(thecellswerepreconditionedwithASX0.1,1.0,and10.0nmol·L-1,respectively).Thecellviabilitywas measured by MTT method. The level of reactive oxygen species( ROS)was determined by DCFH-DA method. The changes of mitochondrial membrane potential( MMP)and apoptosis ratio were detected by JC-1 method and DAPI method,respectively. caspase-3 activity changes of EPCs were detected. Results The cell viability of EPCs was improved with the increasing concentration of ASX. Compared with the model group[(48. 5±4. 3)%],0. 1,1. 0,10. 0 nmol·L-1 ASX significantly increased the cell viabilities[(57. 6±8. 2)%,(77. 6±7. 5)%,and(85. 3±6. 1)%,P﹤0. 05]. The results of DAPI staining revealed that ASX pretreatment could significantly reduce the apoptotic rate of EPCs. The apoptotic rate of the model group was( 27. 8 ± 3. 2)%,while that of ASX+tBHP groups was[(20. 4±2. 9)%,(14. 9±1. 7)%,and(7. 8±0. 7)%,P﹤0. 05],respectively. The data from caspase-3 activity assay indicated that ASX precondition could also remarkably decrease the caspase-3 activity for EPCs. The caspase-3 activity of the model group was(0. 345±0. 018),while that of the ASX+tBHP group were[(0. 291± 0. 013),(0. 209±0. 004),and(0. 169±0. 013),P﹤0. 05],respectively. In addition,treatment with tBHP resulted in an increase of DCF fluorescence,while ASX precondition could decrease the DCF fluorescence,which suggested the accumulation of intercellular ROS for EPCs. Injury of michondrial membrane resulted in the loss of mitochondrial membrane potential( MMP). The MMP detected by JC-1 method revealed that compared with model group,pretreatment of ASX inversed the reduction of MMP. Conclusion Astaxanthin inhibits endothelial progenitor cell apoptosis induced by oxidative stress through inhibiting ROS production,improving the mitochondrial function and down-regulating caspase-3 activity.
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BACKGROUND:Coronary stent implantation can cause blood vessel damage and wal reconstruction, leading to vascular stent restenosis. Studies have found that visfatin is associated with inflammatory reaction, and exhibits an increased expression at the site of plaque rupture in acute myocardial infarction. OBJECTIVE:To investigate the influence of percutaneous coronary intervention on the levels of visfatin in patients with coronary heart disease. METHODS:Thirty patients with acute myocardial infarction within 12 hours after the onset of the chest pain, 30 patients with unstable pectoris and 30 patients with stable angina pectoris were included. Al patients were successfuly treated by percutaneous coronary intervention. Meanwhile, 30 patients only undergoing coronary angiography but not stenting treatment were selected, and another 30 patients without any treatment served as normal control group. RESULTS AND CONCLUSION:According to enzyme-linked immunosorbent method, the visfatin levels of acute myocardial infarction, unstable angina, stable angina and coronary angiography groups continue to rise at pre-operation, 30 minutes, 6 hours, 12 hours, 24 hours after operation, al of which were higher than that in the normal control group (P < 0.05). The results confirmed that within 24 hours after coronary stent implantation the visfatin levels continue to rise.