Rats with congenital hydronephrosis show increased susceptibility to renal ischemia‐reperfusion injury

Many drug candidates have shown significant renoprotective effects in preclinical models; however, there is no clinically used effective pharmacotherapy for acute kidney injury. The failure to translate from bench to bedside could be due to misleading results from experimental animals with undetected congenital kidney defects. This study was performed to assess the effects of congenital hydronephrosis on the functional capacity of tubular renal transporters as well as kidney sensitivity to ischemia‐reperfusion (I‐R)‐induced injury in male Wistar rats. Ultrasonography was used to distinguish healthy control rats from rats with hydronephrosis. L‐carnitine or furosemide was administered, and serial blood samples were collected and analyzed to assess the effects of hydronephrosis on the pharmacokinetic parameters. Renal injury was induced by clamping the renal pedicles of both kidneys for 30 min with subsequent 24 hr reperfusion. The prevalence of hydronephrosis reached ~30%. The plasma concentrations after administration of L‐carnitine or furosemide were similar in both groups. I‐R induced more pronounced renal injury in the hydronephrotic rats than the control rats, which was evident by a significantly higher kidney injury molecule‐1 concentration and lower creatinine concentration in the urine of the hydronephrotic rats than the control rats. After I‐R, the gene expression levels of renal injury markers were significantly higher in the hydronephrotic kidneys than in the kidneys of control group animals. In conclusion, our results demonstrate that hydronephrotic kidneys are more susceptible to I‐R‐induced damage than healthy kidneys. Unilateral hydronephrosis does not affect the pharmacokinetics of substances secreted or absorbed in the renal tubules.