4.4. Myeloperoxidase (MPO) Activity Assay

The activity of MPO in colon tissues of mice was detected by an MPO kit (Nanjing Jiancheng Bioengineering Institute, Nanjing, China). Briefly, colon tissue was homogenized in 50 mmol/L potassium phosphate buffered saline (PBS, pH 6.0) at 1:19, including 0.5% hexadecyltrimethylammonium hydroxide. The supernatant reacted with the mixed solution including 3,3′-dimethoxybenzidine and hydrogen peroxide (H₂O₂), pH 6.0. MPO activity was evaluated by analyzing the H₂O₂-dependent oxidation of 3,3′-dimethoxybenzidine.