Drug treatment and assessment of DSS-induced colitis
For the induction of DSS-induced experimental colitis, C57BL/6 mice were randomly divided into four groups, including a normal control group, a vehicle control group, and two drug treatment groups (60 mg/kg PHI and 20 mg/kg PHI). The normal group received sterile water throughout the experiment, while the other groups were given 2% DSS for 7 days and followed by a 3-day recovery period on regular drinking water. During the experiment, the body-weight loss ratio, stool consistency and rectal bleeding were assessed daily according to the described criterion (see Table 1). The total score of these parameters represents the disease activity index (DAI). On day 10, mice were anesthetized using intraperitoneal injection of 4% chloral hydrate. The peripheral blood, colon, and mesenteric lymph nodes were collected for subsequent analysis.
Table 1. Criteria for DAI: weight loss, stool consistency and fecal blood