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

Aims: We aimed to investigate the anti-hypertensive effect of radiofrequency (RE) renal denervation (RDN) in an animal model of hypertension. Materials and methods: RE 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 findings: RF-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 (353 +/- 9.5 vs. 21.4 +/- 8.6 ng/mL/h, p < 0.01). Significance: RF-RDN demonstrated an anti-hypertensive effect with a reduction of renal tissue norepinephrine and plasma renin activity in SHR. (C) 2014 Elsevier Inc All rights reserved.