The beneficial effects of swimming training preconditioning on reducing vascular reactivity in chronic myocardial infarction: Independent of NO production

Background There is evidence of the beneficial effects of swimming training (ST) after myocardial infarction (MI) on heart function. However, the actions of ST preconditioning (STP) in MI on vascular function require further research. Objective This work focused on evaluating whether STP has beneficial nitric oxide-mediated effects on cardiovascular function in chronic MI. Methods Four months female Wistar rats were randomized as follows: (1) sham; (2) six weeks left anterior descending coronary artery ligation (LADL); (3) LADL + valsartan; (4) ST + LADL. Eight weeks of STP were performed in the ST + LADL group, then LADL was induced on the estrus stage and evolved for six weeks. The LADL + valsartan group was treated a day after surgery, for six weeks. Subsequently, vascular reactivity to Ang II and phenylephrine in aortic rings, quantification of nitric oxide (NO) on serum, heart, and aorta, and echocardiographic parameters were measured. Results ST + LADL reduced both vasoconstrictors reactivity beyond sham values. Ejection fraction (EF) and shortening fraction (SF) decreased in the LADL group vs sham, while ST + LADL and LADL + valsartan remained unchanged. NO levels decreased in LADL + valsartan and ST + LADL groups compared to sham and LADL groups. Conclusion STP in chronic MI improves cardiac function and reduces vascular reactivity through a non-related NO mechanism.