JNK/ATF2 Pathway Is Involved in Iodinated Contrast Media-Induced Apoptosis

Background/Aims: Notably, activating transcriptional factor 2 (ATF2), a histone-modification gene, is involved in oxidative stress-induced apoptosis. The aim of this study was to clarify the role of ATF2 in contrast media-induced nephropathy. Methods: Human embryonic kidney 293T cells were treated with four different contrast media: ionic high-osmolar diatrizoate; ionic low-osmolar iothalamate; non-ionic low-osmolar iohexol, and non-ionic iso-osmolar iodixanol. The mRNA expression of ATF2 was determined by real-time PCR. Short interfering RNA was used to knock down ATF2 mRNA expression. Phosphorylation of ATF2 was measured by Western blotting. Wistar rats were administered either diatrizoate or a normal saline injection. Apoptosis in kidney tubular cells was determined by the presence of positive TUNEL stain. Results: Diatrizoate, iodixanol and iothalamate, but not iohexol, induced the expression of ATF2 mRNA and phosphorylation of ATF2 in 293T cells in a time-dependent manner. More apoptotic cells were in diatrizoate-treated kidney cells than in the saline injection group (p < 0.00001). Cell death was significantly increased by knockdown ATF2 expression in the presence of diatrizoate, indicating a protective role of ATF2 in contrast media-induced apoptosis. Conclusions: Differential activation of ATF2 by different contrast media provides a new insight into the mechanism and prevention of contrast-induced nephropathy. Copyright (C) 2009 S. Karger AG, Basel