Vitamin D retarded IVDD by inhibiting NF-κB pathway. Results of protein expression of p65, IKKα and IκBα in vivo was determined by Western blotting (A) and real time PCR (B). Results of expression of p65 in vitro was determined by Western blotting (C) and real time PCR (D). (“*” means there is a statistical difference with the control group, “#” means there is a statistical difference with the vehicle group and “**” means there is a statistical difference with the IL-1β group. N number is all 3. p65: vehicle-control. P = 0.000002; low dose-vehicle, P = 0.00032; high dose-vehicle, P = 0.00001. IKKα: vehicle-control. P = 0.000004; low dose-vehicle, P = 0.00032; high dose-vehicle, P = 0.00008. IκBα: vehicle-control. P = 0.00041; low dose-vehicle, P = 0.01042; high dose-vehicle, P = 0.00526. p65: vitamin D-control. P = 0.0001; IL-1β+vitamin D-IL-1β, P = 0.00024).