Involvement of Rho-kinase/IκB-α/NF-κB activation in IL-1β-induced inflammatory response and oxidative stress in human chondrocytes.

It has been clearly indicated that osteoarthritis (OA) is an inflammatory and degenerative disease that could be promoted by Rho-kinase (ROCK); however, little is known about the role of ROCK/inhibitor κB alpha (IκB-α)/nuclear factor-κB (NF-κB) p65 pathway activation in interleukin-1β (IL-1β) induced inflammatory response and oxidative stress in primary human chondrocytes. To test this hypothesis, we focused on determining ROCK-II, IκB-α, p-IκB-α, NF-κB p65, p-NF-κB p65, IL-6, tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), p22, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subtype 4 (NOX4) protein expression, ROCK-II activity, NADPH oxidase levels, and total antioxidant capacity (TAC) in the presence and absence of ROCK-inhibitor fasudil. IL-1β (2 ng·mL, 24 h) increased the expression of ROCK-II, p-IκB-α, NF-κB p65, p-NF-κB p65, IL-6, TNF-α, COX-2, and p22 proteins, and decreased the expression of IκB-α, and the NOX4 protein level did not alter. ROCK activity and NADPH oxidase levels were increased, whereas the TAC was decreased by IL-1β. Fasudil (10-10 M) reversed all these changes induced by IL-1β. These results demonstrate that ROCK/IκB-α/NF-κB p65 pathway activation contributes to the IL-1β-induced inflammatory response and oxidative stress, and thus, ROCK inhibition might be a beneficial treatment option for OA patients mainly based on its anti-inflammatory and antioxidant effects.