PTGS2 and osteoarthritis: A key inflammatory cytokine, interleukin (IL)-1β, induces an acute inflammation such as osteoarthritis (OA) and extends the inflammatory loop together with other proinflammatory cytokines and inflammatory mediators such as IL-6, tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX2), and prostaglandin E2 (PGE2) [2].