IL-7 causes proteoglycan release, but not nitric oxide production, in cartilage explants. Cartilage explants were stimulated for 72 hours with 10 ng/ml recombinant human IL-7 before media collection. (a) Medium was analyed for sulfated glycosaminoglycan (sGAG) using the dimethylmethylene blue assay and normalized for the wet weight of the tissue. (b) Total nitrite was measured in the media as a marker for nitric oxide production using commercially available colorimetric nitrate/nitrite assay kit. Results represent four experiments.