Oxidative stress caused by activation of NADPH oxidase 4 promotes contrast-induced acute kidney injury
(A) HK-2 cells were exposed to iohexol for 30 min. Nox1, Nox2, Nox3, Nox4, and Nox5 mRNA levels after iohexol exposure were measured by quantitative real-time PCR. (B) HK-2 cells were exposed to iohexol for 0 min, 1 min, 5 min, 10 min, 30 min, 1 h, 2 h, and 24 h. For examination of the long-term viability of HK-2 cells after iohexol exposure, the medium containing iohexol was removed after 1 or 2 h and replaced with fresh serum-free medium for 23 and 22 h (1/23 and 2/22 h, respectively). Nox4 (NOX4) mRNA expression after iohexol exposure was measured by quantitative real-time PCR. Nox4 protein levels were measured by western blotting. Data are the mean ± SD (n = 5). *p < 0.05 and ***p < 0.001 versus the control.