Objective Several studies have indicated that miR-15a,miR-15b and miR-16 may be the important regulators of apoptosis.Since attenuate apoptosis could protect myocardium and reduce infarction size,the present study was...Objective Several studies have indicated that miR-15a,miR-15b and miR-16 may be the important regulators of apoptosis.Since attenuate apoptosis could protect myocardium and reduce infarction size,the present study was aimed to find out whether these miRNAs participate in regulating myocardial ischemia reperfusion （I/R） injury.Methods Apoptosis in mice hearts subjected to I/R was detected by TUNEL assay in vivo,while flow cytometry analysis followed by Annexin V/PI double stain in vitro was used to detect apoptosis in cultured cardiomyocytes which were subjected to hypoxia/reoxygenation （H/R）.Taqman real-time quantitative PCR was used to confirm whether miR-15a/15b/16 were involved in the regulation of cardiac I/R and H/R.Results Compared to those of the controls,I/R or H/R induced apoptosis of cardiomyocytes was significantly iucreased both in vivo （24.4％ ± 9.4％ vs.2.2％ ± 1.9％,P ＜ 0.01,n =5） and in vitro （14.12％ ±0.92％ vs.2.22％ ± 0.08％）.The expression of miR-15a and miR-15b,but not miR-16,was increased in the mice I/R model,and the results were consistent in the H/R model.Conclusions Our data indicate miR-15 and miR-15b are up-regulated in response to cardiac I/R injury,therefore,down-regulation of miR- 15a/b may be a promising strategy to reduce myocardial apoptosis induced by cardiac I/R injury.展开更多
Objective. To study the mechanism and effects of blood perfusion to the acute ischemic region of myocardium through Ho-YAG laser channels with myocardial contrast echocardiography. Methods. To produce the model of acu...Objective. To study the mechanism and effects of blood perfusion to the acute ischemic region of myocardium through Ho-YAG laser channels with myocardial contrast echocardiography. Methods. To produce the model of acute myocardial ischemia,we partially ligated the left anterior decending(LAD)coronary artery of canine hearts between lst.and 2nd.diagonal branches and then performed transmyocardial revascularization in this region with Ho-YAG laser.Myocardial contrast echocardiography was made with a new generation of ultrasound contrast agent and second harmonic imaging of this region before,after ischemia and after laser revascularization.Pictures were taken with “R” wave trigger skill. Results.Acoustic density derterming in the ischemia region (anterior wall)with MCE(myocardial contrast echocardiography)was obviously decreased(540±181) after the LAD was ligated,as compared with before(1169±161, P<001).It was increased remarkably after transmyocardial laser revascularizatuon(TMLR)(112±201, P<001)as compared with that when ischemia and approximated to that before ischemia(P>005).There were no differences in acoustic density in the lateral wall(as control)among these comprehensive three periods(P>005).Contrast in the laser region developed one cardiac cycle ahead of that in the non-ischemic normal region. Conclusion.Acute ischemic myocardium can be perfused by oxygenated blood from the left ventricle through Ho-YAG laser channels.Evidence of blood perfusion through laser channels during systolic phase was detected,and myocardial contrast ultrasonography using intravenous perfluorocarbon-exposed sonicated dextrose albumin rnay be regarded as a reliable method in the study of transmyocardial revascularization.展开更多
文摘Objective Several studies have indicated that miR-15a,miR-15b and miR-16 may be the important regulators of apoptosis.Since attenuate apoptosis could protect myocardium and reduce infarction size,the present study was aimed to find out whether these miRNAs participate in regulating myocardial ischemia reperfusion （I/R） injury.Methods Apoptosis in mice hearts subjected to I/R was detected by TUNEL assay in vivo,while flow cytometry analysis followed by Annexin V/PI double stain in vitro was used to detect apoptosis in cultured cardiomyocytes which were subjected to hypoxia/reoxygenation （H/R）.Taqman real-time quantitative PCR was used to confirm whether miR-15a/15b/16 were involved in the regulation of cardiac I/R and H/R.Results Compared to those of the controls,I/R or H/R induced apoptosis of cardiomyocytes was significantly iucreased both in vivo （24.4％ ± 9.4％ vs.2.2％ ± 1.9％,P ＜ 0.01,n =5） and in vitro （14.12％ ±0.92％ vs.2.22％ ± 0.08％）.The expression of miR-15a and miR-15b,but not miR-16,was increased in the mice I/R model,and the results were consistent in the H/R model.Conclusions Our data indicate miR-15 and miR-15b are up-regulated in response to cardiac I/R injury,therefore,down-regulation of miR- 15a/b may be a promising strategy to reduce myocardial apoptosis induced by cardiac I/R injury.
文摘Objective. To study the mechanism and effects of blood perfusion to the acute ischemic region of myocardium through Ho-YAG laser channels with myocardial contrast echocardiography. Methods. To produce the model of acute myocardial ischemia,we partially ligated the left anterior decending(LAD)coronary artery of canine hearts between lst.and 2nd.diagonal branches and then performed transmyocardial revascularization in this region with Ho-YAG laser.Myocardial contrast echocardiography was made with a new generation of ultrasound contrast agent and second harmonic imaging of this region before,after ischemia and after laser revascularization.Pictures were taken with “R” wave trigger skill. Results.Acoustic density derterming in the ischemia region (anterior wall)with MCE(myocardial contrast echocardiography)was obviously decreased(540±181) after the LAD was ligated,as compared with before(1169±161, P<001).It was increased remarkably after transmyocardial laser revascularizatuon(TMLR)(112±201, P<001)as compared with that when ischemia and approximated to that before ischemia(P>005).There were no differences in acoustic density in the lateral wall(as control)among these comprehensive three periods(P>005).Contrast in the laser region developed one cardiac cycle ahead of that in the non-ischemic normal region. Conclusion.Acute ischemic myocardium can be perfused by oxygenated blood from the left ventricle through Ho-YAG laser channels.Evidence of blood perfusion through laser channels during systolic phase was detected,and myocardial contrast ultrasonography using intravenous perfluorocarbon-exposed sonicated dextrose albumin rnay be regarded as a reliable method in the study of transmyocardial revascularization.
