Sod assay kit a001 3

Normally, oxidative stress assay covers the detection of superoxide dismutase (SOD) and glutathione (GSH) from the treated colon epithelial cells. The assay was performed as described by Chen et al. [15 (link)] with slight modifications. Colon epithelial cells undergoing treatment were digested with trypsin enzyme, washed twice with PBS, and collected by centrifugation (4 °C, 1000 × g, 5 min). The harvested colon epithelial cells were homogenized (1:10, w/v) in cold (4 °C) PBS. The lysed cells were centrifuged (10,000× g, 15 min, 4 °C) and the supernatants were used as the enzyme source. The activity of SOD (Units/mL) and content of GSH (mg/mL) for the treated colon epithelial cells were evaluated using kits (SOD assay kit, A001-3; reduced GSH assay kit, A006-1) purchased from Nanjing Jiancheng Bioengineering, Inc. (Nanjing, Jiangsu, China), according to the manufacturer’s instructions.

Serum biochemical parameters were measured by routine automated laboratory methods. Insulin levels were measured by a commercial ELISA kit (MEA448Mu, Wuhan USCN Business Co., Ltd., Wuhan, China) according to the manufacturer’s instruction. The intra-assay coefficient of variation was 4.0%. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated as described previously (Yan et al., 2017 (link)). SOD activities and MDA levels in tissues and serum were measured by the SOD assay kit (A001-3, Nanjing Jiancheng Bioengineering Institute, Nanjing, China) and MDA assay kit (A003-1, Nanjing Jiancheng Bioengineering Institute, Nanjing, China), respectively, according to the instruction manual.