Figure 2.

Western ligand blotting analysis of insulin-like growth factor (IGF)-binding proteins (IGFBPs) secreted by human osteoarthritis (OA) chondrocytes or human OA cartilage. Aliquots of the 48-hour secretion medium of confluent OA chondrocytes or cartilage explants were electrophoresed and electroblotted onto a nitrocellulose membrane. IGFBPs were detected by incubating the membrane with a mixture of ¹²⁵I-labeled insulin-like growth factor (IGF)-1 and ¹²⁵I-labeled IGF-2, followed by autoradiography. Shown are two and three representative specimens of IGFBP-containing media from chondrocytes and cartilage explants, respectively.