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

Abstract

To investigate the impact of renal denervation on the blood pressure, plasma renalase content and expression of renalase and tyrosine hydroxylase (TH) in the idney of spontaneous hypertensive (SH) rats and to explore the role of renal denervation in lowering the blood pressure. SH rats were randomly assigned into a baseline group, a surgery (renal denervation) group, a sham group and a control group (n=48). WKY rats matched in age (n=12) served as a baseline control group. All rats were housed until 12 weeks old. Then, the rats in the baseline group and the WKY group were sacrificed whose blood and kidney were collected for examination. In the renal denervation group, the sham group and the control group, the blood pressure was monitored continuously. One week and 6 weeks after the renal denervation, 6 rats in each group were sacrificed whose blood and kidney were collected. ELISA was employed to measure the plasma renalase and Western blot assay done to detect the expression of TH and renalase in the kidney. Compared with WKY rats, blood pressure significantly increased and TH protein expression markedly elevated (P<0.05) in SH rats in the baseline group, but plasma renalase content and protein expression of renalase in the kidney dramatically reduced (P<0.05). One week after the surgery, the mean arterial pressure and TH protein expression in the surgery group were lowered compared with the baseline group and dramatically reduced compared with the sham group and the control group (P<0.05). In the surgery group, the renalase level was markedly increased compared with the baseline group, the sham group, and the control group (P<0.05). Six weeks after the renal denervation, the mean arterial pressure and TH level in the surgery group were significantly increased but the renalase content and expression markedly reduced compared with those 1 week, but there were no marked differences among the surgery group, the sham group, and the control group (P>0.05). No pronounced differences in the above variables were found between the sham group and the control group at any time point (P>0.05). Renal denervation can lower the blood pressure, which may attribute to the suppression of sympathetic nerves, increase in plasma renalase content and renalase expression in the kidney.