Inhalation of Hydrogen Gas Is Beneficial for Preventing Contrast-Induced Acute Kidney Injury in Rats.

Background: The present study aimed at investigating the effect of a novel antioxidant, hydrogen (H₂) gas, on the severity of contrast-induced acute kidney injury (CIAKI) in a rat model. Methods: CIAKI was induced in rats by intravenous injection of a contrast medium, Ioversol, in addition to reagents inhibiting prostaglandin and nitric oxide synthesis. During the injection of these reagents, the rats inhaled H₂ gas or control gas. Results: One day after the injection, serum levels of urea nitrogen were significantly lower in H₂ gas-inhaling CIAKI rats (17.6 ± 2.3 mg/dl) than those in control gas-treated CIAKI rats (36.0 ± 7.3 mg/dl), although they both were elevated as compared to untreated rats (14.9 ± 0.9 mg/dl). Consistently, creatinine clearance in H₂ gas-treated CIAKI rats was higher than that in control gas-treated counterparts. Renal histological analysis revealed that the formation of proteinaceous casts and tubular necrosis was improved by H₂ gas inhalation. Mechanistic analyses showed that inhalation of H₂ gas significantly reduced renal cell apoptosis, expression of cleaved caspase 3, and expression of an oxidative stress marker, 8-hydroxydeoxyguanosine, in injured kidneys. Conclusion: Results suggest that H₂ gas inhalation is effective in ameliorating the severity of CIAKI in rats by reducing renal cell apoptosis and oxidative stress. © 2015 S. Karger AG, Basel.