Can hydration protect against intravenous contrast-induced acute kidney injury?

Objective: To evaluate the effect of saline hydration on contrast-induced acute kidney injury in a rat model of diabetes mellitus. Materials and Methods: This was a quantitative, preclinical experimental study. A total of 28 male Wistar rats were randomized into four groups: citrate (control); diabetes mellitus-only; diabetes mellitus + iodinated contrast (6 mL/kg iothalamate meglumine); and diabetes mellitus + iodinated contrast + saline (NaCl 0.9%, 12 mL/kg). Physiological parameters, renal hemodynamics, inulin clearance (as a proxy for renal function), urinary albumin, and oxidative injury were assessed. Statistical significance was set at p < 0.05. Results: In the diabetes mellitus-only group, there was sustained hyperglycemia, weight loss, polyphagia, polyuria, polydipsia, and renal hypertrophy, with significant differences in comparison with the control group. In the diabetes mellitus + iodinated contrast group (in comparison with the diabetes mellitus-only group), there was an additional reduction in the mean renal blood flow (2.1 ± 0.7 mL/min vs. 6.9 ± 0.8 mL/min), greater mean renal vascular resistance, lower mean inulin clearance (0.17 ± 0.02 mL/min vs. 0.85 ± 0.13 mL/min), and a higher mean level of urinary neutrophil gelatinase-associated lipocalin (318.1 ± 52.6 pg/mL vs. 42.2 ± 42.6 pg/mL), together with higher hydrogen peroxide concentrations, as well as elevated lipid peroxidation and thiol consumption in renal tissue. Pretreatment with saline hydration averted those changes (p < 0.05 for all). Conclusion: Saline hydration attenuated the impairment of renal function and hemodynamics by reducing redox imbalance in contrast-induced acute kidney injury.