Changes in ischemic myocardium following marrow mesenchymal stem cells implantation by echocardiography in rabbits / 中国组织工程研究

ABSTRACT

BACKGROUND: Recent studies indicate that bone marrow messenchymal stem cells (MSCs) can repairinjured myocardium and improve cardiac functions. However, there are still no effective non-invasive methods to detect ventricular wall motion, survival status of transplanted cells, and microcirculation improvement after MSCsimplantation. OBJECTIVE: To detect the effects of MSCs implantation on the cardiac function of ischemic myoeardium and investigate changes of tissue acoustics characteristics by using integrated backscatter (IBS) and Doppler tissue imaging (DT1). DESIGN, TIME AND SETTING: Completely randomized grouping design, and randomized controlled study, which was carried out in the Department of Cardiology, Renmin Hospital of Wuhan University from December 2004 to June 2005 (important laboratory of 211 government). MATERIALS Forty-eight male rabbits with irrespective of gender were used for study. Anti-troponin T (TnT) antibody was provided by Maxim Company, USA; anti-bromodeoxyuridine (BrdU) antibody by Sigma Company, USA; Sonos 5500 echocardiography by HP Company, USA.METHODS: Forty-eight rabbits were randomly divided into model group and implantation group. Model of myocardium infarction was created in rabbits by left anterior descending coronary artery (LAD) ligation. Three days after modeling, autologous bone marrow MSCs were injected into crossed myocardium between infarction and non-infarction regions based on 5 injected points.MAIN OUTCOME MEASURES: Indicators including ventricular size, ventricular wall thickness, and ejection fraction (EF) in the left ventricle (LV) were measured with routine echocardiography one day before myocardial infarction, two weeks after myocardial infarction, and four weeks after implantation. IBS and DTI might detect the anterior backscatter parameters (AII, or IB) and ventricular wall motion parameters (PPI, or CVIB) to calculate the average backscatter scores and backscatter cycle changes. DTI was used to measure peak systolic flow velocity (VS), peak early diastolic flow velocity (VE), and peak late diastolic flow velocity (VA) of the middle and basal segments of the anterior wall of left ventricle. Finally, animals were sacrificed by anesthesia, and myocardial infarction region was stained with 5-Brdu immunohistochemical staining, and anti-TnT staining. RESULTS: Twelve rabbits were excluded because of death after operation.① Echocardiography Imaging of 36 rabbits were clear in 1 day before myocardial infarction, 2 weeks after myocardial infarction, and 4 weeks after implantation. The sizes and systolic function of LV in 36 rabbits were normal before operation. Two weeks after operation, the sizes of LV became larger, the anterior wall of LV became thinner, and systolic range became weaker even disappeared. EF, CVIB, Vs, and Ve were lower (P < 0.05) and All was higher in both groups than pre-operation (P < 0.05). Four weeks after implantation, compared with control group, left ventricular diastolic diameter (LVDd) was smaller and systolic range became larger, All descended. EF, Vs, Ve and CVIB increased (P < 0.05).② Myocardial immunohistochemical detection Numerous of Brdu-labeled positive cells were scattered, and anti-TnT was positive, which clearly showed horizontal stria of myocardium. However, normal myocardium was negative. CONCLUSION: Bone marrow MSCs after implantation can survive in ischemic myocardium and improve cardiac function. IBS and DTI can real-timely and exactly detect functional changes of infarction myocardium after bone marrow MSCs implantation.