Quantitative changes of infarcted myocardium according to different time of treatment for human mesenchymal stem cell transplantation in rat with myocardial infarction

Abstract

Background and Objectives: Mesenchymal stem cell (MSC) therapy has shown potential benefits for repairing myocardial damage. But, the therapeutic effect is modest and the optimal time for treatment is not established. The aim of this study was to assess an optimal time of treatment for acute myocardial infarction (AMI) in rat model.Methods: AMI was induced by ligation of the left anterior descending coronary artery in male Sprague-Dawley (SD) rats. Human bone marrow MSCs were directly injected into the infarct boarder zone at 1 hour and 1 week after AMI. Control groups were injected equal volume of phosphate buffered saline (PBS). The hearts were excised, and the left ventricle was sectioned into 4 slices. Quantitative analysis of infarct size was done by using the SigmaScan planimetry measurement.Results: The infarct area of 1 hour group (N=5) was reduced compared with 1 week group (N=5) and control group (N=3) (1 hour group vs. 1 week group vs. control group: 12.86 ± 6.55 vs. 17.52 ± 6.64 vs. 17.93 ± 4.10). But there was no statistical significance according to different time of treatment (p = 0.295 for 1 hour group vs. 1 week group; p = 0.279 for 1 hour group vs. control group; p = 0.926 for 1 week group vs. control group).Conclusion: Our study failed to demonstrate the optimal time for treatment and the effect of MSC in rats with AMI. But, numerical improvement of infarct area in 1 hour group seems to be confirmed in further large study..