Effects of Renal Denervation from the Intima and the Adventitia of Renal Arteries on Renal Sympathetic Nerve Activity in Dogs: A Comparative Study

Objectives: This study was designed to observe the efficacy and safety of renal denervation from the inside and outside of renal arteries. Methods: Fourteen beagles were randomly divided into a control group (n = 4) and treatment group (n = 10). One renal artery in every beagle of the treatment group was randomly assigned to an intimal group (10 renal arteries) which underwent percutaneous renal denervation from the inside, and another renal artery was assigned to an adventitial group (10 renal arteries) which underwent renal denervation from the outside by laparotomy. Results: Compared with the intimal group, the renal norepinephrine (NE) concentration in the adventitial group had significantly decreased (p = 0.003) at 3 months postsurgery. Renal artery HE staining showed that the perineurium from the adventitial group appeared thickened. Western blotting showed that renal tissue tyrosine hydroxylase (TH) protein expression in the adventitial group was significantly lower than that in the intimal group (p < 0.01) at 3 months postsurgery. There was a renal artery stenosis and a renal atrophy in the intimal group after 1 month of follow-up. Conclusion: The inhibitory effect on renal sympathetic nerve activity was more effective in the adventitial group than the intimal group, and renal denervation in the former group was safe.