Study On Effect Of Renal Sympathetic Nerve Radiofrequency Ablation In Canine Models For Hypertension Norepinephrine Overflow Rate And Sympathetic Nerve Activity

BackgroundHypertension is recognized as a series of major risk factors for cardiovascular disease,as the prevention and control of cardiovascular diseases which cannot be evasived. InClinical there is a considerable part of the patients whose blood pressure is not under thecontrol of the140/90mm Hg following the target value, for people with diabetes or kidneydisease failed to fall to130/80mm Hg is defined as the obstinate hypertension,after usingadequate and reasonable3or more antihypertensive drug treatment including diuretics, It isone of the difficulties on this class of therapeutic strategies for patients with hypertension.Many studies on the role of the sympathetic nervous system in hypertension weremaked in the early30’s，especially the maintaining mechanism of action in hypertensionand, especially surgical operation denervating the Sympathetic nervous system is improvedfor several times, but once abandoned because of it is not significant and the side effects. Inrecent years a series of basic experimental and clinical trials have made progress around therole of sympathetic nervous system in hypertension, we make to this one problem withfurther understanding; the renal sympathetic nerve radiofrequency ablation for thetreatment of intractable hypertension is expected to gain revolutionary headway more as aresult of radiofrequency ablation technology continues to mature, and the achievements ofablation treatment of rapid arrhythmia arrhythmia, though the denervation on abnormalcardiac conduction pathway.The catecholamines (epinephrine, including noradrenaline and dopamine) whichreleased by the sympathetic nervous system (Sympathetic nervous system, SNS) regulatethe cardiac output and renin release through an effect on beta1receptors, acting on thealpha1receptor in the regulation of systemic and renal vasoconstriction, in beta2receptorsin regulation of renal vasodilation comprehensive above, effect on blood pressure and renal function of regulation. maintaining stable blood pressure.by short-acting (regulatevasoconstriction, vascular resistance and heart rate) and long-term (regulation of reninrelease and renal tubular sodium and water reabsorption) In the normal population. Thehyperexcitability of sympathetic nerve can lead to increased blood pressure, renal plasmaflow decreased, sodium retention and activation of the renin-angiotensin-aldosteronesystem, thus speeding up the progress of the disease, increase the rate of cardiovascularevents.From the view of anatomical and physiological basis, sympathetic nervous systemconcrols kidneys, there are rich sympathetic nerve fiber in glomerular mesangial area, thejuxtaglomerular apparatus and tubular, especially the proximal convoluted tubule and theloop of Henle. On the other hand, the kidney concrol the excitability though the systemicsympathetic nervous system via afferent renal nerve and central nervous system.The renal sympathetic nerve impulses increase when sympathetic nerve impulsesenhances in cerebral cortex, medulla oblongata in hypertensive, Pressure continues at ahigh level because of rise to the term sodium retention, increased the extracellular fluid.While renal sympathetic nerve radiofrequency ablation inhibitor the neural activitythrough the kidney partial denervation, the neural activity inhibition, then influence therelease of catecholamines substance, reaching the inhibition effect on blood pressure.Objective1、To evaluate the effectiveness and mechanism.of the renal sympathetic nerveradiofrequency ablation in the treatment of abdominal aortic coarctation hypertensive dogs2、To explore the optimal ablation method of renal artery of radiofrequency ablation inthe treatment of hypertensionMethods1、To establish hypertension model though abdominal aortic coarctation with20healthy mongrel dogs. Which were randomly divided into treatment group and controlgroup, each group of10, to confirm the ligation sites of similar degree and correct withabdominal aortic angiography.To Observate blood pressure before and after canine modelcontrol group is significantly increased, the control group modeling and norepinephrineoverflow rate and sympathetic nerve activity is obvious changes. The treatment groupcompared with the control group, norepinephrine overflow rate and sympathetic nerve activity if there is a significant change, to verify validity of the RSD operation in treatmentof hypertensive canine model.2、To take renal sympathetic nerve radiofrequency ablation on treatment groups at onemonth after modeling.which divided into unilateral renal artery ablation group and bilateralrenal artery ablation group.3、To monitor canine anterior brachial systolic blood pressure (systolic blood pressure,SBP), diastolic blood pressure (diastolic blood pressure, DBP) and mean arterial pressure(mean arterial blood pressure, MAP) in control group respectively in modeling before, onemonth after modeling, two month after modeling and three after modeling.4、To monitor renal sympathetic nerve activity in control group in modeling before,one month after modeling, two month after modeling and three after modeling. with thesame method monitoring renal sympathetic nerve activity in treatment group in ablationbefore, after ablation immediately and two months after ablation.5、To measure norepinephrine overflow rate in treatment group at ablation before, onemonth after ablation, two months after ablation while control group at one month aftermodeling、two months after modeling and three months after modelingResult1、It showed that the location of abdominal aortic coarctation is above the double renalartery bifurcation stenosis about40~60%in treatment group at onemonth after modeling.2、The blood pressure were obviously elevated in control group at one month afterModeling、two months after Modeling、three months after Modeling compared withmodeling before.3. The norepinephrine overflow rate have significantly elevated in control group at onemonth after Modeling、two months after Modeling、three months after Modeling comparedwith modeling before. operation group increased at ablation before compared to modelingbefore.while decreased at one month after ablation、two months after ablation compared tomodeling before.4. The wave bottom of neural activity width, amplitude increases at one month afterModeling compared to modeling before, suggest that renal sympathetic nerve activitydecreased but the impulse frequency impulse activity has increased; there have nosignificantly change at three months after modeling compared to one month after modeling.The waveform and frequency did not change significantly but amplitudedecreased immediately after operation.indicating renal sympathetic nerve activity decreasedobviously, proved that RSD operation for renal sympathetic nerve activity inhibition isobvious. wave amplitude increased, sympathetic nerve activity increased slightly at twomonths after ablation,.5. The blood pressure decreased significantly in bilateral renal artery ablation group atone month after ablation、two months after ablation compared to unilateral renal arteryablation group,while norepinephrine overflow rate significantly decreased.Conclusion1、Hypertensive canine model can be successfully established though abdominal aorticbanding.2、The coarctation of abdominal aorta in canine hypertension can be effectivlly andsafely controlled though renal sympathetic nerve radiofrequency ablation.3、The hypertension can be controlled more effectively, and without increasing sideeffects in bilateral renal artery radiofrequency ablation compared with unilateral inabdominal aortic coarctation in canine.