In Vitro Comparison of Responses of Osteoarthritic and Normal Articular Cartilageexplants to Dynamic Compression

Introduction In the pursuit of developing an in vitro model for the study of chondrocyte metabolism and the development of osteoarthritis (OA), it is important to mimic as closely as possible the in vivo environment. It is well known that chondrocyte metabolism is affected by mechanical stimuli through cellular signaling pathways. Therefore, mechanical load is an integral part of the in vivo environment and a loading regimen needs to be developed that can mimic that environment such that chondrocyte metabolism is maintained at homeostatic levels. In the present study, one dynamic compressive loading regimen was applied to full-thickness cartilage explants obtained from the femoral head of normal and osteoarthritic dogs for up to two weeks in vitro. Effects of disease and load on chondrocyte metabolism were assessed by determining levels of expression of relevant genes and proteoglycan and collagen content in explants. Proteoglycan and collagen content i n culture media were also determined.