Effects of stem cells therapy combined with aerobic exercise on ventricular remodeling in rats with acute myocardial infarction / 中华物理医学与康复杂志

ABSTRACT

Objective:To explore the effect of supplementing stem cell therapy with aerobic exercise in left ventricle remodeling after myocardial infarction.Methods:Sixty 6-week-old male Wistar rats had acute myocardial infarction induced by ligation of the anterior descending coronary artery. They were then randomly divided into a model group, a stem cell group, an exercise group and an observation group. Another ten healthy Wistar rats formed a sham operation group. The rats in the stem cell and observation groups were infused with a suspension of bone marrow mesenchymal stem cells through the tail vein. Beginning four weeks later, the exercise and observation groups underwent 60 minutes of aerobic treadmill exercise 5 days per week for 8 weeks. At the beginning and end of the eight weeks the rats′ exercise performance was evaluated using a graded treadmill exercise test. And after the last training session cardiac structure and function were detected using ultrasound imaging. Tissue was then collected from the left ventricles and the collagen volume fractions were calculated. The expression of myocardial brain natriuretic peptide (BNP), heavy chain β-myosin (β-MHC) and α-MHC mRNA was detected using real-time fluorescence quantitative PCRs.Results:Compared with the sham operation group, the time and distance to exhaustion shortened significantly in the model group, with a significant decrease in the average maximum running speed, left ventricle ejection fraction (LVEF), left ventricle shortening fraction (LVFS), expression of α-MHC and the α-MHC/β-MHC ratio. There was a significant increase in the average resting heart rate, collagen volume fraction, expression of BNP and β-MHC in the model group. Compared with the model group, there was a significant increase in the average LVEF and LVFS of the stem cell group as well as in the time and distance to exhaustion, maximum running speed, expression of α-MHC and in the α-MHC/β-MHC ratio of the observation group, but a significant decrease in the average collagen volume fraction of the stem cell group compared with the observation group, together with the resting heart rate, collagen volume fraction, the expression of BNP and of β-MHC. Compared with the stem cell group, the observation group showed a significant increase in the average time and distance to exhaustion, maximum running speed, expression of α-MHC and the α-MHC/β-MHC ratio, with a significant decrease in the average resting heart rate, collagen volume fraction, expression of BNP and β-MHC.Conclusion:Aerobic exercise or stem cell therapy alone can inhibit left ventricular remodeling and improve cardiac function after myocardial infarction, at least in rats. The combination of the two treatments has a synergistic effect and can further enhance the effect of stem cell therapy.