ABSTRACT
Bone marrow mesenchymal stem cells (MSCs) have shown potential for cardiac repair following myocardial injury, but this approach is limited by their poor viability after transplantation. The present study was to investigate whether trimetazidine (TMZ) could improve survival of MSCs in an ex vitro model of hypoxia, as well as survival, differentiation, and subsequent activities of transplanted MSCs in rat hearts with acute myocardial infarction (AMI). MSCs at passage 3 were examined for their viability and apoptosis under a transmission electron microscope, and by using flow cytometry following culture in serum-free medium and exposure to hypoxia (5% CO(2), 95% N(2)) for 12 h with or without TMZ. Thirty Wistar rats were divided into 3 groups (n=10 each group), including group I (AMI control), group II (MSCs transplantation alone), and group III (TMZ+MSCs). Rat MSCs (4×10(7)) were injected into peri-infarct myocardium (MSCs group and TMZ+MSCs group) 30 min after coronary artery ligation. The rats in TMZ+MSCs group were additionally fed on TMZ (2.08 mg·kg(-1)·day(-1)) from day 3 before AMI to day 28 after AMI. Cardiac structure and function were assessed by echocardiography at 28th day after transplantation. Blood samples were collected before the start of TMZ therapy (baseline), and 24 and 48 h after AMI, and inflammatory cytokines (CRP, TNF-α) were measured. Then the survival and differentiation of transplanted cells in vivo were detected by immunofluorescent staining. The cellular apoptosis in the peri-infarct region was detected by using TUNEL assay. Furthermore, apoptosis-related proteins (Bcl-2, Bax) within the post-infarcted myocardium were detected by using Western blotting. In hypoxic culture, the TMZ-treated MSCs displayed a two-fold decrease in apoptosis under serum-free medium and hypoxia environment. In vivo, cardiac infarct size was significantly reduced, and cardiac function significantly improved in MSCs and TMZ+MSCs groups as compared with those in the AMI control group. Combined treatment of TMZ with MSCs implantation demonstrated further decreased MSCs apoptosis, further increased MSCs viability, further decreased infarct size, and further improved cardiac function as compared with MSCs alone. The baseline levels of inflammatory cytokines (CRP, TNF-α) had no significant difference among the groups. In contrast, all parameters at 24 h were lower in TMZ+MSCs group than those in MSCs group. Furthermore, Western blotting indicated that the expression of anti-apoptotic protein Bcl-2 was up-regulated, while the pro-apoptotic protein Bax was down-regulated in the TMZ+MSCs group, compared with that in the MSCs group. It is suggested that implantation of MSCs combined with TMZ treatment is superior to MSCs monotherapy for MSCs viability and cardiac function recovery.
ABSTRACT
Objective To observe the rat cardiac size and cardiac function changes before and after trimetazidine administration plus bone-marrow stem cells transplanting through echocardiography.Methods Forty wistar rats were divided into the following 4 groups randomly:control group (T),myocardial infarction group (Ⅱ),bone marrow stem calls transplantation group (Ⅲ),and bone marrow stem cells transplantation plus trimetazidine administration group(Ⅳ).The rats' left anterior coronary artery in group Ⅱ,Ⅲ and Ⅳwas ligated to produce myocardial infarction model,then bone-marrow stem cells were injected around the infarcted area into the later two groups.Furthermore,rats in group Ⅳ were administrated with trimetazidine.The size and systolic function of the hearts were measured 4 weeks after transplantation.The left ventricular systolic pressure(LVSP) and the end-diastolic pressure(LVEDP) were also measured at the end of experiment.Results The left ventricular diameter of rats in group Ⅲ and Ⅳ was smaller than that in group Ⅱ,and the ventricular systolic function increased,LVSP increased and LVEDP decreased statistically in group Ⅲ and Ⅳ.the amelioration of cardiac size and function was significantly notable in group Ⅳ than that in group Ⅲ.Conclusions Bone marrow stem cells transplantation can release the enlargement of left ventricle and improve cardiac function after myocardial infarction.The therapeutic efficacy can be further elevated if administrated with trimetazidine simultaneously.