Zinc Preconditioning Provides Cytoprotection following Iodinated Contrast Media Exposure in In Vitro Models

METHODS: Normal human proximal renal kidney cells (HK-2) were preconditioned with either increasing doses of ZnCl(2) or control. Following this preconditioning, cells were exposed to increasing concentrations of Iohexol 300 mg I(2)/ml for four hours. Key outcome measures included cell survival (MTT colorimetric assay) and ROS generation (H(2)DCFDA fluorescence assay). RESULTS: Contrast media induced a dose-dependent reduction in survival of HK-2 cells. Compared to control, contrast media at 150, 225, and 300 mg I(2)/ml resulted in 69.5% (SD 8.8%), 37.3% (SD 4.8%), and 4.8% (SD 6.6%) cell survival, respectively (p < 0.001). Preconditioning with 37.5 μM and 50 μM ZnCl(2) increased cell survival by 173% (SD 27.8%) (p < 0.001) and 219% (SD 32.2%) (p < 0.001), respectively, compared to control preconditioning. Zinc preconditioning resulted in a reduction of ROS generation. Zinc pre-conditioning with 37.5 μM μM ZnCl(2) reduced ROS generation by 46% (p < 0.001) compared to control pre-conditioning. CONCLUSIONS: Zinc preconditioning reduces oxidative stress following exposure to radiographic contrast media which in turn results in increased survival of renal cells. Translation of this in vitro finding in animal models will lay the foundation for future use of zinc preconditioning against contrast induced nephropathy.