Anti-hypertensive effect of radiofrequency renal denervation in spontaneously hypertensive rats

Abstract

AimsWe aimed to investigate the anti-hypertensive effect of radiofrequency (RF) renal denervation (RDN) in an animal model of hypertension. Materials and methodsRF energy was delivered to bilateral renal arteries through a 2Fr catheter with opening abdomen in 8 spontaneously hypertensive rats (SHRs) and 8 Wistar–Kyoto rats (WKYs). Sham operation was performed in other 8 SHRs and 8 WKYs. Blood pressure (BP), heart rate (HR), and urinary norepinephrine excretion were followed up for 3months. Plasma and renal tissue concentrations of norepinephrine and plasma renin activity were measured 3months after the procedure. The RDN was confirmed by a decrease in renal tissue norepinephrine. Key findingsRF-RDN restrained a spontaneous rise in systolic BP (46±12% increase from 158±8 to 230±14mmHg vs. 21±18% increase from 165±9 to 197±20mmHg, p=0.01) and diastolic BP (55±27% increase from 117±9 to 179±23mmHg vs. 28±13% increase from 120±7 to 154±13mmHg, p=0.04) in SHRs; however, WKYs were not affected. Although there were no changes in HR and systemic norepinephrine, the renal tissue norepinephrine was decreased by RF-RDN in both SHR (302±41 vs. 159±44ng/g kidney, p<0.01) and WKY (203±33 vs. 145±26ng/g kidney, p=0.01). Plasma renin activity was reduced by the RF-RDN only in SHR (35.3±9.5 vs. 21.4±8.6ng/mL/h, p<0.01). SignificanceRF-RDN demonstrated an anti-hypertensive effect with a reduction of renal tissue norepinephrine and plasma renin activity in SHR.