PHI reduced the infiltration of inflammatory cells
Neutrophils and macrophages infiltrations are recognized as evaluative parameters for the severity degree of colitis, and flow cytometry was used to assess changes in the immune cell populations in MLN and peripheral blood. The population of monocytes (CD11b+), macrophages (CD11b+F4/80+), neutrophils (CD11b+Ly6G+), and dendritic cells (CD11b+CD11c+) were significantly increased in both MLN and peripheral blood of DSS-induced UC mice. However, both high and low doses of PHI were found to reduce the population of macrophages in MLN and peripheral blood monocyte cells, with high doses of PHI having an inhibitory effect on neutrophils of PBMC (Fig. 4A-B). In TNBS-induced mice, the population of macrophages decreased, and PHI reduced the level, which was consistent with the findings in DSS-induced mice(Fig. 4C-D). Immunofluorescent staining with F4/80 showed severe infiltrations of macrophages in DSS-induced mice colon, which were reduced by PHI (Fig. 4E), suggesting that future research may focus on macrophages’ role in the mechanism of action of PHI.