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
In order to study the mechanisms of high frequency stimulation ( HFS), we designed an in vitro device to deliver extracellular electrical stimulation to live cells in culture, using the same parameters as in the surgical treatment of Parkinson's disease (PD). The system was made of a 24 wells culture plate electrified with titanium wire bridges or two titanium wires placed parallel in a culture dish of 10 centimetres diameter. The extremities of the series of wells were connected to a constant current generator. The result showed that this system had no toxicity on GH3 and PC12 cell cultures. Preliminary experiences demonstrate that this system is suitable for the study with DNA and protein chip technologies.