MMP9 and Duchenne muscular dystrophy: In the double knockout mice (DMD/iNOS-/-), a clear mitigation of DMD induced-iNOS, cytokines (TNF-α, and IL1β), Nox4, NPT, M1 macrophages, MMP9, and increase in CD4+ and CD8+ cells, diaphragm atrophy, and alveolar leakage might be observed.