Therapeutic Value Of Renal Denervation By Three Different Renal Denervation Methods In Adult Spontaneous Hypertensive Rats

Background The contribution of renal sympathetic nerve activity to the development of hypertension has been convincingly demonstrated in both preclinical and human experiments. Renal sympathetic nerves play a prominent role in the pathogenesis of several forms of hypertension. Sympathetic nerve modulation was associated with high morbidity, mortality and long-term complications past. Krum H reported that a percutaneous catheter-based approach was applied to selectively ablate the renal sympathetic nerves recently. They achieved dramatic effective hypotensive effects without severe complications.. However, Their study was not a prospective controlled clinical trial and absence of a control group.Objectives To explore method of renal artery nerves ablation to achieve effective renal denervation. Evaluate the safety and effective of renal denervation in established hypertension and initially explore the mechanisms of hypotensive responses to renal denervation.Methods 12 weeks old male spontaneous hypertensive rats were randomly subjected to group of URSNA(n=18), CRD(n=18), BRSNA(n=18) and sham operation Sham(n=12).1. Basal indexes were monitored in different groups before the operation performed, which including the body weight, SBP and DBP, serum renin, Angâ…¡and NE concentration,. collect and calculate the urinary volume in 24 hours, measure urinary sodium concentration.2. Renal arteries ablation procedure using clamping electrode were performed by three strategies:radiofrequency power was 2W,5W and 10W respectively. Renal arteries ablation procedure with 20J and 25J.Total radio-frequency time was 2min and the interval period was 30s.3. Select the proper strategy to perform the renal arteries ablation therapy, including URSNA and BRSNA. CRD and Sham.4. Blood pressure and heart rate were measured per week. Intake and output of sodium and water were measured at 2,4,6 and 8 weeks after operation. Serum renin, ANGâ…¡and NE) concentration were measured. NE concentratrions of kidney were also measured. Renal artery structure and renal blood rate were observed by the CEUS.5. Kideny and heart were observed by histomorphologic methods.Results1. The continued increased blood pressure in SHR was delayed and significantly reduced by CRD over 8 weeks period. Both the BRSNA and URSNA procedure did not prevent the development of hypertension in SHR.2. Attenuation of increasing blood pressure was associated with decreasing RAS and increasing sodium water outputs in CRD group.3. NE concentration of kidey was significantly decreased in CRD group and was slightly decreased in renal artery ablation groups.4. Renal ablation procedure was not associated with the change of renal artery structure and renal blood rate.Conclusions1. Renal ablation preocedure using radiofrequency power 5W, intermittent 20S, total time 2min could destroy the renal nerves in adult SHRs.2. Renal denervation may delay the development of hypertension in SHR. But it may not been an effective therapeutic method in the long-term control of hypertension in adult SHRs.3. The hypotensive mechanism of renal denervation was due to depression of RAS and increase of urinary sodium excretion,which was not associated with depression of SNS.