A NEW PRESSURE CHAMBER TO STUDY THE BIOSYNTHETIC RESPONSE OF ARTICULAR-CARTILAGE TO MECHANICAL LOADING

A prototype chamber was used to apply a precise cyclic or static load on articular cartilage explants under sterile conditions. A variable p ressure, pneumatic controller was constructed to power the chamber's a ir cylinder, capable of applying, with a porous load platen, loads of up to 10 MPa at cycles ranging from 0 to 10 Hz. Pig articular cartilag e explants were maintained successfully in this chamber for 2 days und er cyclic mechanical loading of 0.5 Hz, 0.5 MPa. Explants remained ste rile, viable and metabolically active. Cartilage responded to this loa d with a decreased synthesis of fibronectin and a small but statistica lly significant elevation in proteoglycan content. Similar but less ex tensive effects on fibronectin synthesis were observed with the small static load (0.016 MPa) inherent in the design of the chamber.