Abstract
Arachidonic acid is metabolized to epoxyeicosatrienoic acids (EETs) by CYP epoxygenases, and EETs are kidney protective in multiple pathologies. We determined the ability of an EET analogue, EET-A, to mitigate experimental radiation nephropathy. The kidney expression of the EET producing enzyme CYP2C11 was lower in rats that received total body irradiation (TBI rat) compared with non-irradiated control. At 12 weeks after TBI, the rats had higher systolic blood pressure and impaired renal afferent arteriolar function compared with control, and EET-A or captopril mitigated these abnormalities. The TBI rats had 3-fold higher blood urea nitrogen (BUN) compared with control, and EET-A or captopril decreased BUN by 40-60%. The urine albumin/creatinine ratio was increased 94-fold in TBI rats, and EET-A or captopril attenuated that increase by 60-90%. In TBI rats, nephrinuria was elevated 30-fold and EET-A or captopril decreased it by 50-90%. Renal interstitial fibrosis, tubular and glomerular injury were present in the TBI rats, and each was decreased by EET-A or captopril. We further demonstrated elevated renal parenchymal apoptosis in TBI rats, which was mitigated by EET-A or captopril. Additional studies revealed that captopril or EET-A mitigated renal apoptosis by acting on the p53/Fas/FasL (Fas ligand) apoptotic pathway. The present study demonstrates a novel EET analogue-based strategy for mitigation of experimental radiation nephropathy by improving renal afferent arteriolar function and by decreasing renal apoptosis.