Background: Prophylactic mineralocorticoid receptor (MR) antagonism with spironolactone (Sp) in rats completely prevents renal damage induced by ischemia. Because acute renal ischemia cannot typically be predicted, this study was designed to investigate whether Sp could prevent renal injury after an ischemic/reperfusion insult.
Methods: Six groups of male Wistar rats were studied: rats that received a sham abdominal operation (S); rats that underwent 20 min of ischemia and reperfusion for 24 h (I/R) and four groups of rats treated with Sp (20 mg/kg) 0, 3, 6 or 9 h after ischemia.
Results: As expected, I/R resulted in renal dysfunction characterized by a fall in renal blood flow and glomerular filtration rate and severe tubular injury which was confirmed by a significant increase in tubular damage biomarkers including kidney injury molecule-1, heat shock protein 72 and urinary protein excretion. The renal injury induced by I/R was in part due to Rho-kinase, endothelin and angiotensin II type 1 receptor upregulation. Interestingly, Sp administration at 0 and 3 h after ischemia completely reversed and prevented the damage induced by I/R. The protection induced by Sp given 6 h after ischemia was partial, but no protection was observed by administering Sp 9 h after ischemia.
Conclusion: Our results show that MR antagonism administered, either immediately or 3 h after I/R, effectively prevented ischemic acute renal injury, indicating that spironolactone is a promising agent for preventing acute kidney injury once an ischemic insult has occurred.