MMP2 and osteoarthritis: Similarly, in osteoarthritis, PEA therapy significantly reduced levels of pro-inflammatory mediators, including leukotriene B4, tumor necrosis factor-α, interleukin-1β, and prostaglandin E2, as well as cartilage-degrading enzymes such as matrix metalloproteinase-2 (MMP-2), MMP-3, MMP-9, and MMP-13.