MMP9 and inflammatory bowel disease: In inflammatory bowel disease, Nrf2/HO-1expression decreased MMP-9 and MMP-7, finally helping to reduce inflammation; The skin damage caused by UV irradiation is more severe in Nrf2 knockout mice than in WT mice, and MMP-9 and MIP-2 (macrophage inflammatory protein-2 is a crucial modulator of neutrophil recruitment) levels are much higher [150, 151].