Impact of renal denervation on renalase expression in adult rats with spontaneous hypertension

The aim of this study was to investigate the impact of renal denervation on the blood pressure, plasma renalase content and expression of renalase and tyrosine hydroxylase (TH) in the kidney of spontaneous hypertensive (SH) rats and to explore the mechanism of renal denervation involved in lowering blood pressure. SH rats (n=48) were randomly assigned to baseline, surgery (renal denervation), sham and control groups. WKY rats matched in age (n=12) served as the baseline control group. All rats were housed until they were 12 weeks old. The rats in the baseline group and the WKY group rats were sacrificed, and blood and kidney were collected for examination. In the renal denervation, sham and control groups, the blood pressure was continuously monitored. One and six weeks after renal denervation, 6 rats in each group were sacrificed, and blood and kidney were collected for examination. ELISA was employed to measure the plasma renalase, and western blot analysis was performed to detect the expression of TH and renalase in the kidney. Compared with the WKY rats, SH rats in the baseline group had significantly increased blood pressure and markedly elevated TH protein expression (P<0.05), but dramatically reduced plasma renalase content and protein expression of renalase in the kidney (P<0.05). One week after surgery, the mean arterial pressure and TH protein expression in the surgery group was lowered compared with the baseline group and dramatically reduced when compared with the sham and control groups (P<0.05). In the surgery group, renalase levels were markedly increased compared with the baseline, sham and control groups (P<0.05). Six weeks after renal denervation, the mean arterial pressure and TH levels in the surgery group were significantly increased while the renalase content and expression were markedly reduced compared with those at week 1, however, there were no marked differences among the surgery, sham and control groups (P>0.05). Moreover, no pronounced differences in the above variables were found between the sham and control groups at any timepoint (P>0.05). Renal denervation can lower blood pressure, which may be attributed to the suppression of sympathetic nerves, increase in plasma renalase content and renalase expression in the kidney.