BACKGROUND:Exercise can elicit generation of coronary col ateral circulation through numerous pro-angiogenic growth factors. It is not enough via a single factor to clearly definite signaling pathways for the generation of col ateral circulation. Many pro-angiogenic growth factors are involved in kal ikrein-kinin system, and there is no report about exercise effects on this system.
OBJECTIVE:To study effects of exercise training on bradykinin expression in rats with myocardial infarction.
METHODS:Thirty Wistar rats were randomly assigned to control group, myocardial infarction group and exercises training group. Rats in the control group were subjected to thoracotomy with no coronary artery ligation. Rats in the other two groups were modeled. In the exercise training group, 3 days after myocardial infarction, rats were subjected to 30-minute exercise training on treadmil , once a day for 4 weeks. At the terminal of the experiment, blood samples were obtained to analyze bradykinin expression by enzyme linked immunosorbent assay, and the myocardium was sampled to analyze relative blood flow by microsphere method.
RESULTS AND CONCLUSION:After exercise training, bradykinin level in the exercise training group was significantly higher than that in the myocardial infarction group (P<0.001). At the end of experiment, the relative blood flows of the exercise training and myocardial infarction groups were both increased compared with before experiment (P<0.05, P<0.001). At the end of experiment, the relative blood flow of the exercise training group was significantly higher than that of the myocardial infarction group (P<0.01). In al the three groups, bradykinin level was significantly correlated with the relative blood flow in the myocardium. These findings indicate exercises training can improve bradykinin expression apparently and increase blood flow in the myocardium, which il ustrates that the kal ikrein-kinin system plays an important role in exercise induced angiogenesis.