Fibronectin fragments upregulate insulin-like growth factor binding proteins in chondrocytes.

Unlabelled: Addition of fibronectin fragments (Fn-fs) to cultured cartilage explants has been shown to mediate extensive cartilage matrix degradation followed by anabolic responses.

Objective: To determine whether specific Fn-fs regulate cartilage metabolism through a mechanism, in part, involving insulin-like growth factor (IGF) and insulin-like growth factor binding proteins (IGFBPs).

Methods: Primary bovine articular chondrocyte cultures were treated with Fn-fs.