Renal denervation in established hypertension in the spontaneously hypertensive stroke prone rat

Abstract

To understand recent data showing ablation of renal nerves in drug-resistant hypertensive patients results in a sustained reduction in blood pressure (BP), renal denervation was performed in the established phase of hypertension (HTN) in the spontaneous hypertensive stroke prone rat (SHRSP). BP was recorded telemetrically from salt loaded male SHRSP which underwent bilateral renal denervation (RDX) or sham surgery. BP was similar in the groups prior to surgery (Sham: 186.6±8.9 mmHg, RDX: 189.0±9.8 mmHg). RDX showed a significant decrease in BP 8hrs after surgery compared to Sham (RDX: −35.7±13.07mmHg, Sham: −0.95±9.6mmHg). 24hrs post surgery, RDX BP was not significantly different from Sham (RDX: 181.7±9.4mmHg, Sham: 190.1±9.4mmHg), but the small difference was maintained for 8 days. Although not statistically significant, BP reduction after ganglionic blockade after surgery was larger in Sham (−89.0±14.5 mm Hg) than RDX (−70.8±22.6 mmHg). Thiazide diuretic caused a greater fall in BP in sham compared to RDX (Sham: −34.3±4.4mmHg, RDX: −21.5±3.6mmHg). Renal nerves may play a significant role in maintaining established HTN in SHRSP, but other mechanisms rapidly compensate for the loss of renal nerve influences. SHRSP may be a good model to understand the hypotensive effects of renal nerve ablation, and post-intervention BP treatment strategies, in human patients with drug-resistant HTN.