Chondrocyte growth medium supplementmix

Human IL-1β and human TNF were purchased from PeproTech (Rocky Hill, NJ, USA) and dissolved in water. Forskolin was purchased from Tocris Bioscience (Bristol, UK) and dissolved in dimethyl sulfoxide (DMSO)/water (final DMSO dilution 1:200). Β-Endorphin, Nociceptin and Dynorphin A were purchased from Cayman Chemical (Ann Arbor, MI, USA) and dissolved in water. Pronase E was obtained from Merck KGaA (Darmstadt, Germany), and collagenase P from Roche Diagnostics GmbH (Mannheim, Germany). The chondrocyte culture medium contains Chondrocyte Basal Medium + 10% Chondrocyte Growth Medium SupplementMix (both from PromoCell GmbH, Heidelberg, Germany) + 1% penicillin/streptomycin solution (Life Technologies Europe BV, NN Bleiswijk, The Netherlands). For all stimulation experiments, stock solutions of cytokines, Forskolin and opioid neuropeptides were diluted to the final concentration in chondrocyte culture medium.

Human IL-1β was purchased from PeproTech (Rocky Hill, NJ, USA). N⁶-(1-iminoethyl)-L-lysine hydrochloride (L-NIL), forskolin, 8-Bromoadenosine-3′,5′-cyclic monophosphate sodium salt (8-Bromo-cAMP), dorsomorphin dihydrochloride, and A769662 were all purchased from Tocris Bioscience (Bristol, UK). Forskolin and A769662 were dissolved in DMSO/water (final DMSO dilution 1:200 and 1:5000, respectively), all other substances were dissolved in water. PGE₂ was from Cayman Chemical (Ann Arbor, MI, USA) and was dissolved in DMSO/water (final DMSO dilution 1:5000). Pronase E was obtained from Merck KGaA (Darmstadt, Germany), and collagenase P from Roche Diagnostics GmbH (Mannheim, Germany). The chondrocytes culture medium contains Chondrocyte Basal Medium + 10% Chondrocyte Growth Medium SupplementMix (both from PromoCell GmbH, Heidelberg, Germany) + 1% Penicillin/Streptomycin Solution (Life Technologies Europe BV, NN Bleiswijk, Netherlands).