In primary chondrocytes of meniscectomy osteoarthritis of C57BL/6 mice model, nicotine (1, 10, and 100 μM) decreased the IL-1β-induced IL-6 and MMP3/MMP13 expression in a dose-dependent manner in the wild type but not in α7 nAChR-/- type, indicating that nicotine’s effect is also mediated by α7 nAchR in this non-neuronal cholinergic system (67). The gene discussed is CHRNA7; the disease is osteoarthritis.