Effects of Renal Sympathetic Denervation on Post-Myocardial Infarction Cardiac Remodeling in Rats

OBJECTIVE To investigate the therapeutic effects of renal denervation (RD) on post- myocardial infarction (MI) cardiac remodeling in rats, the most optimal time for intervention and the sustainability of these effects. METHODS One hundred SPF male Wistar rats were randomly assigned to N group (Normal, n=10), MI group(MI, n=20),RD group (RD, n=10), RD3+MI (MI three days after RD, n=20), MI1+RD (RD one day after MI, n=20), MI7+RD (RD seven days after MI, n=20). MI was produced through thoracotomic ligation of the anterior descending artery. RD was performed through laparotomic stripping of the renal arteriovenous adventitial sympathetic nerve. Left ventricular function, hemodynamics, plasma BNP, urine volume, urine sodium excretion and other indicators were measured four weeks after MI. RESULTS (1) The left ventricular function of the MI group significantly declined (EF<40%), plasma BNP was elevated, urine output was significantly reduced, and 24-hour urine sodium excretion was significantly reduced. (2) Denervation can be achieved by surgically stripping the arteriovenous adventitia, approximately 3 mm from the abdominal aorta. (3) In rats with RD3+MI, MI1+RD and MI7+RD, compared with MI rats respectively, the LVEF was significantly improved (75 ± 8.4%,69 ± 3.8%,73 ± 5.5%), hemodynamic indicators were significantly improved, plasma BNP was significantly decreased, and the urine output was significantly increased (21.3 ± 5 ml,23.8 ± 5.4 ml,25.2 ± 8.7 ml). However, the urinary sodium excretion also increased but without significant difference. CONCLUSIONS RD has preventive and therapeutic effects on post-MI cardiac remodeling.These effects can be sustained for at least four weeks, but there were no significant differences between denervation procedures performed at different times in the course of illness. Cardiac function, hemodynamics, urine volume and urine sodium excretion in normal rats were not affected by RD.