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

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 3 months. Plasma and renal tissue concentrations of norepinephrine and plasma renin activity were measured 3 months 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 ± 14 mm Hg vs. 21 ± 18% increase from 165 ± 9 to 197 ± 20 mm Hg, p = 0.01) and diastolic BP (55 ± 27% increase from 117 ± 9 to 179 ± 23 mm Hg vs. 28 ± 13% increase from 120 ± 7 to 154 ± 13 mm Hg, 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 ± 44 ng/g kidney, p < 0.01) and WKY (203 ± 33 vs. 145 ± 26 ng/g kidney, p = 0.01). Plasma renin activity was reduced by the RF-RDN only in SHR (35.3 ± 9.5 vs. 21.4 ± 8.6 ng/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.