title: Optimal time for mesenchymal stem cell transplantation in rats with myocardial infarction.
abstract: BACKGROUND
  Bone marrow mesenchymal stem cell (MSC) transplantation is a promising strategy in the treatment of myocardial infarction (MI). However, the time for transplanting cells remains controversial. The aim of this study was to find an optimal time point for cell transplantation.
  
  
  METHODS
  MSCs were isolated and cultured from Sprague-Dawley (SD) rats. MI model was set up in SD rats by permanent ligation of left anterior descending coronary artery. MSCs were directly injected into the infarct border zone at 1 h, 1 week and 2 weeks after MI, respectively. Sham-operated and MI control groups received equal volume of phosphate buffered saline (PBS). At 4 weeks after MI, cardiac function was assessed by echocardiography; vessel density was analyzed on hematoxylin-eosin stained slides by light microscopy; the apoptosis of cardiomyocytes was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay; the expressions of proteins were analyzed by Western blot.
  
  
  RESULTS
  MSC transplantation improved cardiac function, reduced the apoptosis of cardiomyocytes and increased vessel density. These benefits were more obvious in 1-week group than in 1-h and 2-week groups. There are more obvious increases in the ratio of bcl-2/bax and the expression of vascular endothelial growth factor (VEGF) and more obvious decreases in the expression of cleaved-caspase-3 in 1-week group than those in other two groups.
  
  
  CONCLUSIONS
  MSC transplantation was beneficial for the recovery of cardiac function. MSC transplantation at 1 week post-MI exerted the best effects on increases of cardiac function, anti-apoptosis and angiogenesis.
authors.affiliation: Department of Cardiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China. chen_yang_jiang@yahoo.com
authors.forename: Chen-yang
authors.initials: CY
authors.lastname: Jiang
authors.forename: Chun
authors.initials: C
authors.lastname: Gui
authors.forename: Ai-na
authors.initials: AN
authors.lastname: He
authors.forename: Xin-yang
authors.initials: XY
authors.lastname: Hu
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Yun
authors.initials: Y
authors.lastname: Jiang
authors.forename: Jian-an
authors.initials: JA
authors.lastname: Wang