CCL2 and colitis: Research has shown that macrophages isolated from TNBS-induced colitis mice display M1 polarization [42], which may activate signaling pathways such as NF-κB, JAK/STAT, and ERK, releasing large amounts of pro-inflammatory cytokines (TNF-α, IL-1β, IL-23) and chemokines (CXCL8, CCL2) to participate in immune responses.