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Objective:To investigate the regulatory effect of miR-26a in radiation-induced heart disease (RIHD) mice.Methods:C57/BL6 mice were used to establish RIHD models. The cardiac function, fibrosis, the expression levels of collagen 1 (COL1) and connective tissue growth factor (CTGF), and miR-26a were detected in RIHD mice. Whether CTGF was the target gene of miR-26a was verified by dual luciferase kit. Moreover, cardiac fibroblasts were transfected with miR-26a up and miR-26a down lentivirus vectors to construct the miR-26a overexpression and underexpression cell models. The expression of CTGF, proliferation, and apoptosis of cardiac fibroblasts were detected.Results:In the RIHD mice, heart function was decreased, myocardial fibrosis was remodeled, the expression levels of COL1 and CTGF were up-regulated, and the expression level of miR-26a was down-regulated. Dual luciferase reporter assay confirmed that CTGF was the target gene regulated by miR-26a. Overexpression of miR-26a could inhibit the expression of CTGF, suppress the proliferation of cardiac fibroblasts, promote cell apoptosis and secrete collagen. Underexpression of miR-26a yielded the opposite results.Conclusion:MiR-26a affects the function of cardiac fibroblasts by targeting CTGF and probably mediates the process of radiation-induced myocardial fibrosis, which may become a new regulatory target of RIHD.
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Objective:To investigate the regulatory role of microRNA in radiation-induced heart disease (RIHD) in mice and provide a new strategy for its treatment.Methods:Based on the Gene Expression Omnibus database (GSE147241), which includes normal heart tissue and irradiation heart tissue, we conducted bioinformatics research and analysis to determine the differentially-expressed genes. Then, thirty male C57/BL6 mice were randomly divided into the control group, irradiation group and miR-133a overexpression intervention group. The heart received single dose of X-ray 20 Gy in the irradiation group and miR-133a overexpression intervention group, but not in the control group, and then fed for 16 weeks. Cardiac function was assessed by echocardiography. Myocardial fibrosis was detected by Masson staining. The expression levels of miR-133a, CTGF, COL-1 and COL-3 mRNA were detected by qRT-PCR. The expression levels of CTGF, COL-1 and COL-3 proteins were detected by western blot.Results:miR-133a was the differentially-expressed gene between the irradiation and control groups. Overexpression of miR-133a could mitigate the decrease in cardiac function and increase in myocardial collagen content ( P<0.01). Meantime, overexpression of miR-133a could down-regulate the expression levels of CTGF, COL-1, COL-3 mRNA and protein ( P<0.01). Conclusions:Radiation increases the synthesis of collagen and leads to myocardial fibrosis remodeling. Overexpression of miR-133a can alleviate the radiation-induced myocardial fibrosis.
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Objective:To establish the C57BL/6 mouse models of radiation-induced cardiopulmonary dysfunction.Methods:Twenty-four male C57BL/6 mice were randomly divided into the control and irradiation groups. Mice in the irradiation group were irradiated with 20 Gy electron beam and bred for 6 months after irradiation. Cardiac function was assessed using ultrasonography. The partial pressure of oxygen was detected by blood gas analysis. Cell apoptosis was observed by Tunel assay. Myocardial and pulmonary fibrosis was assessed by Masson staining.Results:The LVEF in the irradiation group was (68.60±10.92)%, significantly less compared with (81.75±8.79)% in the control group ( P< 0.01). The apoptotic index of heart in the irraiation group was (23.90±6.60)%, considerably higher than (3.25±3.38)% in the control group ( P< 0.01). The CVF of heart in the irradiation group was (15.42±5.72)%, significantly higher than (1.45±0.64)% in the control group ( P< 0.01). The PaO 2 level in the irradiation group was (86.10±7.60) mmHg, significantly lower compared with (107.16±9.01) mmHg in the control group ( P< 0.01). The apoptotic index of lung in the irradiation group was (27.90±8.94)%, significantly higher than (2.50±3.55)% in the control group ( P<0.01). The CVF of lung in the irradiation group was (17.76±5.77)%, remarkably higher than (2.50±3.55)% in the control group ( P< 0.01). Conclusion:Radiation can induce cardiopulmonary apotosis and fibrosis remodeling, which leads to cardiopulmonary dysfunction, suggesting the successful establishment of C57BL/6 mouse model of radiation-induced cardiopulmonary dysfunction.
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Objective To evaluate the prognostic value of peak ejection rate (PER) and peak filling rate (PFR) in patients with left ventricular systolic dysfunction (LVSD) after acute myocardial infraction (AMI).Methods A total of 123 patients (103 males,20 females,age:(60.6± 11.2) years) with LVSD after AMI who underwent 99Tc-methoxyisobutylisonitnle (MIBI) gated SPECT myocardial perfusion imaging (GSMPI) from January 2014 to December 2015 were retrospectively analyzed.Summed rest score (SRS) and total perfusion deficit (TPD) were acquired by using quantitative perfusion SPECT (QPS) soft-ware.Left ventricular ejection fraction (LVEF),end-diastolic volume (EDV),end-systolic volume (ESV),PER,and PFR were calculated by using quantitative gated SPECT (QGS) software.The clinical parameters of patients were recorded and the cardiac events were taken as the endpoint of follow-up (median time:27 (range:9-50) months).Pearson correlation was used to analyze the correlation between PER and PFR.Receiver operating characteristic (ROC) curve was used to evaluate optimal cut-off values of PER and PFR for predicting cardiac events.Kaplan-Meier survival analysis and Cox proportional hazards model were also used for data analysis.Results There was a great correlation between PER and PFR (r =-0.931,P＜0.001).Optimal cut-off values of PER and PFR for predicting cardiac events were-1.10 EDV/s and 1.09 EDV/s respectively.Kaplan-Meier survival analysis showed that cumulative survival rate without cardiac events was lower in patients (n=48) with-PER≤ 1.10 EDV/s than that in patients (n=75) with-PER＞ 1.10 EDV/s (16.7％ vs 66.7％;x2=60.096,P＜0.001),and the same rate in patients (n=50) with PFR ≤ 1.09 EDV/s was lower than that in patients (n=73) with PFR＞1.09 EDV/s (16.0％ vs 68.5％;x2=74.771,P＜0.001).Cox multivariate analysis showed that PER (hazard ratio (HR)=0.40,95％ CI:0.20-0.83) and PFR (HR=0.22,95％ CI:0.12-0.47) were independent predictors for cardiac events.Conclusion There is a great correlation between PER and PFR in patients with LVSD after AMI and they are independent predictors for cardiac events.
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Objective To investigate the value of local myocardial blood flow and myocardial function parameters in monitoring the dynamic changes of radiation induced heart disease (RIHD) using 13NNH3 PET gated myocardial perfusion imaging(GMPI).Methods Six healthy male Beagle dogs underwent 13N-NH3 PET GMPI 1 week before irradiation and 3,6 and 12 months after irradiation in the anterior wall of the left ventricle with a single dose of 20 Gy.Global myocardial function parameters including left ventricular ejection fraction (LVEF),end-diastolic volume (EDV),end-systolic volume (ESV),and regional myocardial function parameters including wall motion (WM),wall thickening (WT),end-diastolic perfusion (EDP),end-systolic perfusion (ESP) before and after irradiation were compared by repeated measures analysis of variance and paired t test.Results There were no significant changes between EDV,ESV and LVEF at baseline and those at 3 months after irradiation.EDV at 6 months after irradiation still had no change,compared with baseline value and EDV at 3 months after irradiation,but ESV was increased and LVEF was decreased.Twelve months after irradiation,ESV was further expanded,LVEF was further reduced,and EDV began to increase (F values:20.974-177.846,all P＜0.05).Compared with the baseline,WM,WT,EDP and ESP were increased in 10％(2/20),20％(4/20),10％(2/20) and 15％(3/20) of myocardial segments at 3 months after irradiation (t values:14.446-672.315,all P＜0.05);those parameters were decreased in 15％(3/20),20％(4/20),15％(3/20) and 25％(5/20) of myocardial segments at 6 months after irradiation (t values:18.171-723.156,all P＜0.05),and were decreased in 35％(7/20),45％(9/20),40％(8/20) and 60％ (12/20) of myocardial segments at 12 months after irradiation (t values:14.783-711.259,all P＜0.05).Conclusions 13N-NH3 PET GMPI could be used to detect RIHD early and monitor the dynamic development of RIHD.Compared with the global left ventricular function parameters,regional myocardial function parameters (WM,WT,EDP and ESP) are more sensitive,which may be served as the early monitoring indicators for RIHD.