Aim: To assess differences in intrarenal nerves in hypertensive and normotensive rodents with and without concomitant diabetes.
Background: Hypertensive diabetic patients have increased renal sympathetic nerve activity and develop nephropathy at an accelerated rate however little is known of changes in renal sympathetic innervation in either hypertension or diabetes.
Methods: Studies were carried out in hypertensive and diabetic rodents to assess differences in intrarenal innervation. Twenty-three week old hypertensive (BPH/2J) and normotensive (BPN/3J) Schlager mice were killed and perfused with normal saline, cold 4% PFA and kidneys embedded in paraffin. Streptozotocin induced diabetic C57Bl6 and apolipoprotein E knockout (apoE KO) mice were killed after 20 weeks of diabetes and kidneys fixed in 10% NBF before being embedded in paraffin. All kidneys were cut and stained with the neural marker tyrosine hydroxlyase (TH).
Results: There was more staining for TH in cortical tubules of hypertensive mice compared with normotensive controls (26 ± 2% vs 19% ±1% respectively, n=4/group, p<0.05). Diabetic C57Bl6 and apoE KO and appeared to have a redistribution of staining with a greater staining intensity in the distal convoluted tubules. This redistribution also occurred in hypertensive Schlager mice.
Conclusions: These results indicate that intrarenal innervation is greater in the hypertensive kidney and innervation is redistributed in the diabetic kidney, suggesting changes in the neural control of the kidney in such conditions. This has direct implications for the treatment of hypertension and renal disease, especially for the treatment of diabetic and hypertensive kidney disease.