MMP9 and colitis: Another study with DSS colitis in fat-1 mice established decreased cyclooxygenase-2 (COX-2) expression and decreased PGE2 levels in the fat-1 mice and confirmed the suppression of the cytokine response in these mice with a lower expression of IL-18, IL-1α, IL-1β, IL-6, monocyte chemotactic protein-1,2,3 (MCP-1,2,3), matrix metalloproteinase-9 (MMP-9), and TNF-α [26].