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Objective:To investigate the relationship between the expression level of miR-155 and the severity of coronary lesion, and explore the action mechanism.Methods: Peripheral blood mononuclear cells (PBMC) were isolated form blood simple from patients with acute myocardial infarction (AMI), unstable angina (UAP), stable angina (SAP) and chest pain syndrome (CPS). RT-PCR was performed to analysis the expression level of miR-155 in peripheral blood mononuclear cells, plasma and RAW264.7 macrophagocyte. MTT was used to analyze the cell viability of OxLDL treated RAW264.7 macrophagocyte.Results: The expression level of miR-155 in blood sample from coronary heart disease patients was much lower than in the blood sample of non-coronary heart disease (P<0.05). The level of miR-155 in PBMCs was much higher in the blood sample from CPS group than the other three group, and the level of miR-155 in plasma was higher in the CPS group than in the UAP and the AMI group, the difference was statistically significant (P<0.05). The expression level of miR-155 in PBMCs is positively associated with the level in the plasma (r=0.861,P=0.000). OxLDL can induce the expression of miR-155 in RAW264.7 macrophagocyte, decrease the cell viability of RAW264.7 macrophagocyte, and with the concentration and the treatment time of OxLDL increased, the effort become more obvious. The inhibition effort of OxLDL to RAW264.7 macrophagocyte with high miR-155 expression is much lower than the control group, and it is statistically significant after treated for 12, 24 and 48 h.Conclusions: miR-155 plays a protective role in the progression of atherosclerosis, and it may be achieved by reducing the apoptosis effort of OxLDL to RAW264.7 macrophagocyte.
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Objective To evaluate the diagnostic value of high frequency echocardiography on mice with doxorubicin-induced cardiotoxicity and find out the most valuable monitoring indexes for early doxorubicin-induced myocardial damage.Methods Forty mice were divided into doxorubicin-injection group (ADM group) and control group randomly.Twenty mice in each group were injected with doxorubicin and saline at the same dose for 5 weeks continuously.The parameters of cardic function of ADM group and contol group were observed by high-frequency echocardiography after infection.Brain natriuretic peptide (BNP) tested by euzymelinked immunosorbent assay(ELISA) and pathological findings were used as the golden standard.Results ①The left ventricular long axis view and the apical four chamber view could be displayed clearly by transthoracic high-frequency echocardiography.②After 5 weeks intervention,weight,heart rate,left ventricular ejection fraction (LVEF),left ventricular fractional shortening (LVFS),E/A,E wave deceleration time(EDT) and other parameters showed marked difference between ADM group and control group(P ＜0.05).③The decrease of diastolic function was earlier than systolic function in ADM group.④LVEF and E/A presented good negative linear correlation to BNP(r =-0.622,P ＜0.05; r =-0.593,P ＜0.01).EDT showed positive linear correlation to BNP(r =0.501,P ＜0.05).Conclusions Cardic function of mice with doxorubicin-induced myocardial damage could be early evaluated accurately by high-frequency echocardiography,which contained good relativity with BNP.
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Objective To silence Bax gene in H9c2 cells by ultrasound-targeted microbubble destruction(UTMD) combined with polyethylenimine.Methods The shRNA expression plasmid targeting Bax gene was co-treated with microbubbles and polyethylenimine.Then the mixture added to H9c2 cells were irradiated by ultrasound.Grouping:① plasmid group;② Lipofectamine2000 + plasmid group; ③ UTMD + plasmid group;④ PEI + UTMD + plasmid group;⑤ PEI + SonoVue + plasmid group (without ultrasound irradiation).The transfection efficiency was assessed by fluorescence microscope and FCM.The expression of Bax mRNA and protein were detected by RT-PCR and Western Blot.Results Bax shRNA wasn't destroyed by ultrasound exposure.The transfection efficiency of PEI + UTMD + plasmid group was higher than any other groups obviously (P ＜0.05).The result of RT-PCR and Western Blot showed inhibition efficiency of Bax mRNA and protein expression in PEI + UTMD + plasmid group were (69.41 ± 4.91) ％ and (64.09 ± 2.38)％ separately,which were higher than any other groups significantly (P ＜0.05).Conclusions UTMD combined with polyethylenimine can inhibit the expression of Bax gene in H9c2 cells effectively.
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Objective To evaluate the value of high-frequency echocardiography in assessing Bax gene transfer influence on survival of heterotopic cardiac allograft in rats.Methods Thirty rat models of heterotopic heart transplantation were established.Group A received heart transplantation only; Group B received cyclosporin (CsA) after operatiom Group C received ultrasound targeted microbubble destruction (UTMD) combined with Bax-shRNA.All rats were tested by high-frequency echocardiography at day 1,3,6 after transplantation.The ultrasound parameters included left ventricular internal dimension diastole (LVIDd),left ventricular internal dimension systole(LVIDs),left ventricular ejection fraction(LVEF),left ventricular thickness (LVT),left ventricular thickening (LVTR) and so on.The pathologic examinations were carried out on five rats at day 6 after echocardiography exam.The other rats in each group were observed for the survival time of cardiac allograft.Results ①The left ventricular long axis view and the apical four chamber view could be displayed clearly by high-frequency echocardiography.②The survival time of allografts in group C was (16.21 ± 5.01)d,which was longer than that in group B [(11.14 ± 1.72)d,P ＜ 0.05] and group A [(7.26 ± 1.50)d,P ＜0.01].③LVT index got higher after transfection.At day 6,LVEF of group A was lower than group B and C markedly(P ＜0.05) while no significant difference was found between group B and C(P ＞0.05).At day 3 and 6,LVT of group A and B were higher than group C (P ＜0.05) while LVTR was lower(P ＜0.05).Conclusions The Bax gene transfer influence on survival of heterotopic cardiac allograft in rats could be evaluated accurately by high-frequency echocardiography which could assess cardiac structure and function.LVT and LVTR can be considered as early evaluation indexes for its high sensitivity over LVEF.