| Background: There are "three lows" feature in hypertension treatment status(low awareness, low medication, and low control rates)in China and the control rates is lower than 10%. And furthermore there is a higher proportion of refractory hypertension, which more likely to cause target organ damage and seriously threaten health of human being. It is an urgent need to open up new therapeutic approach to improve patient compliance and to make up for lack of drug therapies in Hypertension patient. Krum et al. reported a percutaneous Renal Sympathetic Denervation(RSD) to treat refractory hypertension in 2009 for the first time. This technology showed excellent antihypertensive effect. However, it is still in the exploratory stage, and need to further verify its effectiveness and safety. The standard of choosing patient is still not clear. Whether it can improve cardiac remodeling and other organ damage or not is still not reported.Objective: We observe the effects of RSD on blood pressure with pressure-overload animal model, And study the Preventive Treatment about hypertension cardiac remodeling. We observe the change of norepinephrine, aldosterone, vasopressin and angiotensin II etc. neurohumor factor to make preliminary discussion of it’s molecular mechanism, And we expect to find efficient Clinical screening index.Methods:We established rabbit model of pressure overload hypertension by abdominal aortic constriction. After two months, the abdominal RSD was carried out with radiofrequency ablation catheter. Two months after RSD, the blood pressure values was measured by carotid artery intubation. We also measured left ventricular myocardial index by weighing and calculating, measured ventricular wall depth by cardiac uhrasonography and measured myocardial fibrosis index by sirius scarlet staining method in order to evaluate the level of cardiac remodeling. We tested the change of NE, AVP, Ang II and Ald by ELISA.Results:The rabbit model of hypertension was successfully established by 50% ~ 60% coarctation of the abdominal aorta based on previous reports. Blood pressure in hypertension group is obviously higher than control group and sham-operated group one week after abdominal aortic constriction(P <0.05). Two months after RSD, the rabbit’s heart rate in four groups had no significant difference. The blood pressure in hypertension group remained significantly higher than control group(P <0.05). However, blood pressure in hypertension+ablation group was lower than hypertension group(P <0.05); while control+ablation group and control group had no significant difference. Compared with the Interventricular septum depth(LVPWD), Interventricular septum depth(IVSD), and Left Ventricular Mass Index(LVMI) between hypertension group and control group, these values were increased significantly(P <0.05). However, their values are declining after ablation. Similarly, we observe the degree of cardiac fibrosis by measuring collagen content organization(CVF), and found that myocardial CVF is elevated in the hypertensive group, and also reduced after ablation. This result show us that the level of cardiac remodeling was reduced. NE, Ang II, Ald and AVP were significantly higher in the hypertensive group(P <0.05), And NE, AVP were declined in hypertension+ablation group(P <0.05), but Ald, Ang II had no significant difference.Conclusions : New Zealand rabbits can be stably established pressure-overload hypertension model by abdominal aortic coarctation. RSD can reduce blood pressure caused by pressure-overload, which is good to Cardiac load for a long time. And it also reduces the cardiac hypertrophy and cardiac fibrosis which in a sense alleviates the cardiac remodeling. The results also revealed that NE and AVP level was lower after RSD which meant they play important roles in pressure-overload hypertension animal model after RSD. RSD may prevent and cure cardiac remodeling and reduce blood pressure by adjust the level of AVP and NE, And reduce the activity of renal artery sympathetic ganglion afferent fibers. |
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