2.4. Myeloperoxidase (MPO) activity in the colon

The MPO activity assay was performed per manufacturer's instructions using a kit form Nanjing Jiancheng Co., Ltd (Nanjing, China). In brief, mouse colon tissues were weighed and homogenized, followed by incubation at 37 °C for 15 min. The homogenate was then mixed with a chromogenic agent and incubated at 37 °C for 30 min. Afterward, it was combined with the detection reagent and incubated at 60 °C for 10 min. The absorbance was measured at 460 nm.