T aoc activity

Colonic mucosa samples (about 0.1000 g) were homogenized with ice-cold physiologic saline (1:9, w/v) and centrifuged at 2,000 g for 20 min at 4°C, and the supernatant was obtained for further analyses. The colonic protein concentration was quantified using the Pierce BCA Protein Assay Kit (CoWin Biosciences, Jiangsu, China).
The plasma and colonic mucosa antioxidant enzymes (CAT, SOD, GSH, and GSH-Px) and MDA levels were measured using the commercially available ELISA assay kit (Jiangsu Yutong Biological Technology, Jiangsu, China), as per the manufacturer's instructions. The T-AOC activity and H₂O₂ concentration were detected following the manufacturer's instructions (Nanjing Jiancheng Bioengineering Institute, Nanjing, China). The absorbance values were read on a Multiscan Spectrum Spectrophotometer (Tecan, Infinite M200 Pro, Switzerland). All the redox-related indexes of colonic mucosa were normalized to the total protein concentration of each sample.

The diagnostic kits for assaying SOD activity, GSH-Px activity, CAT activity, T-AOC activity, and LPO and MDA content were purchased from Nanjing Jiancheng Bioengineering Institute (Nanjing, China). Snailase and STZ were purchased from Sigma Chemicals Company (St. Louis, USA). Blood glucose test strips were purchased from Sinocare Biosensing Corporation Limited (Changsha, China). All other chemicals were of analytical grade and purchased from local chemical suppliers.