Ozone preconditioning attenuates contrast-induced nephropathy in rats

Contrast-induced nephropathy (CIN) is an important complication of vascular interventions. Ozone therapy can induce tolerance to ischemic insults, a phenomenon known as ozone oxidative preconditioning (OOP). The aim of this study was to investigate the effects of OOP on CIN.

Thirty-two Wistar rats were randomized into four groups (n = 8). The control group had intravenous saline injection. The contrast media (CM) group had intravenous meglumine/sodium diatrizoate injection to form CIN. The ozone (O3) group received intraperitoneal ozone for 5 d before the induction of CIN. The oxygen (O2) group was given an equal amount of oxygen for 5 d before the induction of CIN. The animals were sacrificed 48 h after the administration of contrast agent or saline. Kidneys were harvested, and blood samples were obtained. Renal function tests, serum and renal tissue malondialdehyde (MDA), and nitric oxide (NO) levels and renal oxidant system parameters were determined. Histologic examination was performed for renal injury.

Serum blood urea nitrogen (BUN), creatinine, and serum and renal MDA were increased after contrast exposure. Renal NO was decreased, and there was prominent tubular necrosis in the CM group. Serum BUN, creatinine, serum and renal MDA, and grade of tubular necrosis were decreased in the O3 group as compared with those in the CM group. The levels of serum and renal NO and renal total antioxidant system in O3 group were higher than the levels in the CM group.

OOP attenuates experimental CIN. This effect is suggested to be mediated by reinforcement of renal antioxidant defenses and maintenance of renal NO levels.