Effects of EX527 on the nuclear factor kappa B (NF-κB) and transforming growth factor beta (TGF-β)/SMAD family member 2 (Smad2) pathways in melatonin (MT)-treated interleukin 1-beta (IL-1β)-treated chondrocytes. (A,B) Western blot (WB) was used to detect the protein expression levels of p65, nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor(p-p65), alpha (IκBα), p-IκBα, transforming growth factor beta (TGF-β1), and Smad family member 2 (Smad2). (C,D) Immunofluorescence (IF) staining was used to check the nuclear entry of p65 and Smad2 in each group. * p < 0.05, ** p < 0.01 (compared to the model group).