The aim of the study was to investigate the effect of sesame oil on acute kidney injury induced by the synergistic action of aminoglycoside and iodinated contrast in rats. Acute kidney injury was induced by a 5-day course of daily gentamicin injections (100 mg/kg of body weight, subcutaneously) and then iodinated contrast (4 ml/kg, intravenously) in male specific-pathogen-free Sprague-Dawley rats. Sesame oil (0.5 ml/kg, orally) was given 1 h before iodinated contrast. Renal function and oxidative stress were assessed 6 h after iodinated contrast injection. Renal function was evaluated by measuring serum blood urea nitrogen and creatinine levels. Renal oxidative stress was assessed by determining renal lipid peroxidation, myeloperoxidase, hydroxyl radical, superoxide anion, nitrite/nitrate, and inducible nitric oxide synthase levels. Sesame oil significantly prevented the rise of serum blood urea nitrogen and creatinine levels. Furthermore, there was a parallel inhibition of the rise in levels of expression of renal lipid peroxidation, myeloperoxidase, hydroxyl radicals, superoxide anion, nitrite/nitrate, and inducible nitric oxide synthase in rats with gentamicin-plus-iodinated contrast-induced acute kidney injury. We conclude that sesame oil may attenuate aminoglycoside-plus-iodinated contrast-induced acute kidney injury by inhibiting renal oxidative stress in rats.The development of radiologic contrast media originated with the use of iodinated contrast medium in radiography in 1918 (18). The use of iodinated contrast medium has been increasing along with the increasing use of diagnostic imaging. It is estimated that more than 80 million patients received iodinated contrast medium in 2003 worldwide (21). Because iodinated contrast is widely used, it is sometimes administered to patients receiving an aminoglycoside. The action of this combination of contrast agents and aminoglycosides against renal hemodynamics and tubular cell function is potentially synergistic (25). In addition, a large cohort study has found that the use of iodinated contrast significantly increased the risk of acute kidney injury (AKI) in patients treated with aminoglycosides (25).Oxidative stress plays an important role in the pathogenesis of iodinated contrast-associated AKI in renally compromised patients (24). The vasoconstriction and renal ischemia caused by contrast media leads to the generation of reactive oxygen species (ROS) and nitric oxide, both of which are involved in the development of renal oxidative stress and tubular cell damage (1,2,20,24). Therefore, inhibiting contrast-associated oxidative stress may be beneficial in preventing iodinated contrast-plus-aminoglycoside-induced renal injury. Sesame oil is a potent antioxidative agent (9)(10)(11)14). Sesame oil potently reduces renal oxidative stress by inhibiting the generation of ROS and nitric oxide in septic rats (9)(10)(11)14). Further, sesame oil protects against gentamicin-induced renal injury by inhibiting renal oxidative stress in rats (17). However, the effect of s...