Aminognanidine Inhibits IL-β-induced Nuclear Transcription Factor Signaling Pathway In Rat Articular Chondrocytes

We used IL-1β to mimic the pathophysiology of OA. To investigate the effects of AG on i NOS and COX-2 expression on interleukin-1β(IL-1β) stimulated rat chondrocytes and whether AG modulate iNOS and COX-2 expression via NF-κB pathway.The third generation was used in this experiment.Base on the concentrations of AG and IL-1β,rat chondrocytes were divided randomly into two groups:X group and Z group. X group consisted of five subgroups : A1 subgroups(control group); B1 subgroup(10 ng/ml IL-1β); D1subgroup(10 ng/m L IL-1β and 0.3 mM AG); D 3 subgroup(10 ng/mL IL-1β and 1mM AG); D5subgroup(10 ng/m L IL-1β and 3 mM AG). Chondrocyte cultures were treated for 2h. Z group consisted of six subgroups: A2 subgroups(control group); B2 subgroup(10 ng/ml IL-1β); C subgroup(3 mM AG); D2 subgroup(10 ng/m L IL-1β and 0.3 mM AG); D 4 subgroup(10 ng/m L IL-1β and 1 mM AG); D6 subgroup(10 ng/m L IL-1β and 3 mM AG). Chondrocyte cultures were treated for 24 h. Protein expression of COX-2, i NOS, NF-κB/p65, IκBα and the phosphorylation levels of NF-κB/p65, IκBα and IKKα/β were investigated by Western blotting. NF-κB/p65 translocation was determined by immunofluorescence staining.The Experiment Result Shows:(1) We found that AG at various concentrations(0.3, 1, 3 mM) significantly reduced IL-1β-induced phosphorylation levels of IKKα/β and IκBα(p < 0.01) and significantly increased the levels of p65 and IκBα(p < 0.01) compared to IL-1β alone. However, AG at the 0.3 mM did not decrease IL-1β-induced phosphorylation levels of p65(p > 0.05). In addition, the levels of p-IKKα/β and p-IκBα were lowest at 1mM AG, and the levels of p65 and IkBα were highest.(2) We found that AG the protein levels of i NOS and COX-2 remarkably reduced(p < 0.01) in chondrocytes with 3 mM AG alone. AG at various concentrations(0.3, 1, 3 mM) significantly reduced IL-1β-induced levels of i NOS and COX-2, and AG reduced the expression of iNOS and COX-2(p < 0.01) in a dose-dependent manner in contrast with chondrocytes stimulated with IL-1βalone.(3) IL-1β markedly induced the translocation of NF-κB p65 from cytoplasm to nuclear in IL-1β-stimulated chondrocytes. AG prevented IL-1β-induced nuclear-translocation of NF-κB p65.The results indicated that AG is able to block nuclear-translocation of NF-κB p65 in rat chondrocytes.The study indicate that AG can downregulation i NOS and COX-2 expression via blocking the NF-κB signaling pathway to protect chondrocytes.