ABSTRACT
[ ABSTRACT] AIM: To evaluate the guiding effect of high-frequency stimulation ( HFS) on renal denervation ( RDN) , and to compare the similarities and differences of blood pressure changes at the time of electrical stimulation and radiofrequency ablation .METHODS:A total of 6 Kunming dogs were included in this study .Renal artery abnormalities were excluded by angiography .High-frequency stimulation and radiofrequency ablation were performed at the same sites from distal to proximal segments of the renal artery .Invasive blood pressure ( BP) was recorded during the whole proce-dure.The change of the blood pressure was analyzed .HE and Masson staining was adopted to detect the structural changes in the wall of the renal artery and surrounding tissues .The immumohistochemical staining for tyrosine hydroxylase ( TH) was used to observe the renal nerve damage after ablation .RESULTS: Electrical stimulation and radiofrequency ablation were delivered in a total of 50 sites.The BP increasing response was induced at 34%sites (n=17), while the rest sites (66%, n=33) had no response.Compared with the baseline , HFS caused the increases in systolic BP of (0.34 ±3.38), (0.41 ±3.04), (10.47 ±5.73), (13.27 ±3.63), (10.17 ±1.87) and (0.78 ±1.87) mmHg in 6 serial 20 s time segments during 120 s of HFS at positive BP response sites .Similarly, the increases in systolic BP by (-0.88 ±3.44) , (-1.64 ±3.47), (13.17 ±3.12), (12.82 ±3.21), (9.50 ±2.68) and ( -6.09 ±2.21) mmHg were observed dur-ing 120 s of ablation procedure at the same sites in 6 serial 20 s time segments .At non-responding sites , HFS and ablation failed to cause a significant increase in systolic BP .The mean area of nerves in the response sites was ( 0.51 ±0.28 ) mm2, whereas that in non-response sites was (0.09 ±0.06) mm2(P<0.01).The average absorbance values of TH in re-nal nerves at ablation and non-ablation sites were 0.031 ±0.015 and 0.085 ±0.018 ( P <0.01 ) , respectively . CONCLUSION:Renal sympathetic nerves can be effectively mapped by HFS .Radiofrequency ablation guided by HFS is valid to injure sympathetic nerves around renal artery .
ABSTRACT
AIM:To investigate the effect of renal denervation ( RDN) by radiofrequency catheter ablation on the expression of aquaporins ( AQP) in dog kidneys .METHODS:Adult Chinese Kunming dogs ( n=12 ) were randomly divided into RDN group and control group (6 for each group).The dogs in RDN group underwent bilateral RDN using ra-diofrequency catheter ablation , and radiofrequency catheter was positioned in bilateral renal artery without ablation in con -trol group.The levels of norepinephrine (NE) and AQP1~3 in the renal tissues were detected 1 month after RDN, and blood pressure (BP) measurements were performed at baseline and 1 month after RDN.RESULTS: The level of NE in RDN group was significantly lower than that in control group (P<0.01).The expression of AQP1~3 in the renal cortex and medulla was lower in RDN group than that in control group .RDN also caused a substantial BP reduction (P<0.05). CONCLUSION:RDN substantially decreases the tissue levels of NE and AQP in dog kidneys , and also decreases BP sig-nificantly , which might be involved in the mechanism of BP reduction by RDN .Renal sympathetic nerve plays an excitatory role in the regulation of AQP in the kidney.