2.4. Determination of Biochemical Parameters
At weeks 0, 4, and 8, each subject was asked to fast for > 12 hours overnight, then blood and urine samples were collected the next morning. After centrifugation (at 3000 rpm, 4 °C for 15 min), aliquots of blood samples were stored at −80 °C until further analysis. Serum lipid profile (TC, LDL cholesterol, HDL cholesterol, triglyceride, apoA1, and apoB), uric acid, glucose, and superoxide dismutase (SOD) were analyzed by the Cobas c702 automatic biochemical analyzer (Roche Diagnostics, Basel, Switzerland). Serum XO activity was detected by commercial kits (Cat NO. BC1095, Solarbio, Beijing, China). Fasting insulin was measured by the Cobas e602 automatic biochemical analyzer (Roche Diagnostics, Switzerland). The HOMA-IR was calculated by the formula: HOMA-IR = [glucose (mmol/L) × insulin (mU/mL)]/22.5. Serum malonaldehyde (MDA, Cat NO. JL11466), allantoin (Cat NO. JL47385), glutathione S-transferase (GST, Cat NO. JL11241), glutathione (GSH, Cat NO. JL10703), glutathione peroxidase (GSH-Px, Cat NO. JL10355), urine 8-iso-prostaglandin F2α (8-iso-PGF2α, Cat NO. JL19022) and 8-hydroxy-2′-deoxyguanosine (8-OHdG, Cat NO. JL11850) were measured by ELISA kits (J&L Biological, Shanghai, China). Urine biomarker values were normalized to urine creatinine concentration, measured by the BS-830 automatic biochemical analyzer (Mindray, Shenzhen, China).