CHRNA7 and osteoarthritis: In the C57BL/6J mouse model of osteoarthritis induced by an injection of monosodium iodoacetate into the knee joint, nicotine (0.5 or 1 mg/kg once daily, i.p., 1 week) reduced mechanical allodynia, cartilage degradation, and the upregulation of MMP9 production by macrophages via α7 nAChR through modulation of the PI3K/Akt/NF-κB pathway (64).