[Value of RNA oxidation product 8-oxo-Gsn in evaluating renal function in patients with chronic kidney disease]

Objective: To investigate the relationship of DNA oxidative product 8-oxo-dGsn and RNA oxidative product 8-oxo-Gsn with chronic kidney disease (CKD). Methods: Between January 2015 and December 2016, 146 cases of CKD (30, 30, 31, 30 and 25 cases of CKD stage 1-5, respectively) were collected in the Department of Nephrology in Beijing Hospital. Among them, 70 cases were male, accounting for 47.95%. The age distribution ranged from 21 to 88 years, with an average age of (56.43±16.79) years. Their fasting blood and morning urine were collected. The levels of 8-oxo-dGsn and 8-oxo-Gsn in plasma and urine were quantified by isotope-diluted liquid chromatography mass spectrometry (MS)/MS (ID-LC-MS/MS). Results: The urine 8-oxo-Gsn/Cr in patients with CKD stage 1-5 was (3.07±1.07) μmol/mol, (3.42±1.34) μmol/mol, (3.72±1.47) μmol/mol, (3.90±1.93) μmol/mol and (3.75±2.26) μmol/mol, respectively. The urinary 8-oxo-Gsn content in CKD stage 4 patients was significantly higher than those of other 4 stages (P<0.05). The serum/urine ratio of 8-oxo-Gsn was 0.02±0.02, 0.03±0.02, 0.06±0.04, 0.10±0.05 and 0.34±0.03, respectively, and in CKD stage 4 and 5 patients, it increased significantly, especially in CKD stage 5 cases (P<0.05). Expression of 8-oxo-Gsn had a good correlation with renal function[the Spearman 's correlation coefficient: serum 8-oxo-Gsn and serum creatinine was 0.629 (P<0.001); urine/serum 8-oxo-Gsn and eGFR was 0.799 (P<0.001); serum/urine 8-oxo-Gsn and serum/urine creatinine was 0.888 (P<0.001)]. With age increasing, CKD patients showed increased RNA oxidation, and 8-oxo-Gsn increased significantly in patients over 60 years (P<0.05). After multiple linear regression analysis, 8-oxo-Gsn was only associated with serum creatinine (β=0.656, t=8.275, P<0.001). Conclusions: Our finding indicates that the RNA oxidation occurs in patients with renal disease, and its oxidation increased as the disease progressing. The significant increase in the ratio of plasma and urinary 8-oxo-Gsn is of great importance on evaluating renal function.