Reactive oxygen species (ROS) generation, inflammation and apoptosis are observed in contrast-induced acute kidney injury (CI-AKI). NOX4, isoform of NADPH oxidase main regulatory enzyme for ROS generation, is mostly expressed in the kidney and co-localized with p22phox. It is investigated the effect of antioxidant, anti-inflammatory and anti-apoptotic montelukast pre-treatment on expression of NOX4, p22phox and NF-κB in preventing CI-AKI in rats in this study. Wistar male rats randomized into four groups: 1. Control (C), 2. CI-AKI (iohexol
3 g iodine/kg), 3. Montelukast (10 mg/kg) (M), 4. M + CI-AKI. Rats sacrificed on the 7th day. Urine and serum creatinine and serum Kidney injury molecule-1 (KIM-1) levels measured. NF-κB, NOX-4, p22phox mRNA and protein expressions, TNF-α, KIM-1 mRNA expressions, ROS and caspase-3 evaluated from kidney tissue. Histological injury scored. ANOVA and Kruskal-Wallis tests were used for analysis parametric and nonparametric data, respectively. p <
0.05 considered statistically significant. Tubular injury score, KIM-1 and caspase-3 levels increased in CI-AKI group compared to C group (p <
0.05). TNF-α, NF-κB, NOX-4, p22phox, KIM-1 mRNA expressions and ROS levels increased in CI-AKI group compared to C group (p <
0.001 and p <
0.05). NF-κB, NOX-4, p22phox protein expressions increased in CI-AKI group compared to C group (p <
0.05) and decreased in the M + CI-AKI group compared to CI-AKI group (p <
0.01, p <
0.05, p <
0.05). TNF-α, NF-κB, NOX-4, p22phox, KIM-1 mRNA expressions and ROS levels decreased with montelukast pre-treatment (p <
0.001). One of the mechanism of increased ROS level in the CI-AKI model is related the increase the expression of NOX4 and p22phox and montelukast pre-treatment has a protective effect by decreasing NOX4 and p22phox mRNA and protein expressions.