TNF and osteoarthritis: Osteoarthritis (OA) involves joint degeneration, especially in the elderly, and is caused by proinflammatory cytokines (e.g., interleukin-1 (IL-1), tumor necrosis factor α (TNFα), oncostatin M (OSM), IL-6, and IL-17), leading to an imbalance in the biochemical processes in articular cartilage [1–3].