Renal denervation abolishes the protective effects of ischaemic preconditioning on function and haemodynamics in ischaemia-reperfused rat kidneys.

Studies were conducted to investigate the role of renal sympathetic nerves in the process of acquiring ischaemic tolerance in ischaemic preconditioned ischaemia-reperfused rat kidneys. Two periods of 3-min occlusion of bilateral renal arteries was performed prior to 30-min bilateral ischaemia and 90-min reperfusion in acute renal denervated or innervated kidneys. The glomerular filtration rate (GFR), fractional excretion of sodium (FENa) and lithium (FELi), and renal blood flow (RBF) were assessed in reperfused kidneys. Ischaemic preconditioning significantly improved values for all these parameters as compared with no treated ischaemia-reperfused kidneys. Denervation caused slight increase in GFR, diuresis and natriuresis without improving RBF after reperfusion. However, protecting effects of ischaemic preconditioning on renal function were disappeared in denervated kidneys, while in innervated kidneys the effects of ischaemic preconditioning were maintained. These results clearly showed that ischaemic preconditioning pre-treatment protects kidneys against ischaemia-reperfusion injury, and the effects are, at least in part, mediated by sympathetic nerves, as the protective effects were abolished by denervation.