A novel rapid technique for quantifying serum oxidized albumin in a mouse model of chronic kidney disease

Oxidative stress serves as both a precursor to and consequence of numerous pathological conditions; however, its assessment remains technically challenging and often imprecise. In the current investigation, we established a rapid high-performance liquid chromatography (HPLC)-based method for quantifying serum oxidized albumin in a murine model of chronic kidney disease (CKD). We optimized the HPLC protocol specifically for measuring oxidized albumin in mice. To validate our methodology, C57BL/6J mice underwent 5/6 nephrectomy (5/6Nx) and were randomly allocated to one of three dietary regimens: standard diet, high-salt diet, or high-salt diet supplemented with Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), a superoxide dismutase mimetic. Following an 8-week intervention period, serum oxidized albumin levels were quantitatively assessed. The key findings were as follows: (i) Our optimized oxidized albumin assay demonstrates excellent intra-day and inter-day reproducibility with a rapid analysis time of 9.5 ‍min; (ii) Oxidized albumin concentrations were significantly increased in high-salt diet-fed animals relative to normal-diet controls, an effect that was attenuated by Tempol administration; (iii) Significant positive correlations were observed between oxidized albumin levels and both urinary protein excretion and 8-isoprostane concentrations. Collectively, we have developed a robust and efficient HPLC-based analytical approach for measuring oxidized albumin in murine serum. This methodology demonstrates both rapid processing capabilities and comparable performance compared to conventional techniques, suggesting substantial utility for investigating oxidative stress in animal models.