Effects of Retinoic Acid in Meniscus and Articular Fibrocartilage

Degeneration of articular cartilage in the knee is related to degenerative and inflammatory joint disease, such as osteoarthritis (OA). The health of the meniscus is of extreme importance to the structural integrity of the knee joint as meniscal tears are associated with the eventual development of OA.  Therefore, it is critical that repair and regeneration mechanisms in the meniscus are explored. Previous studies have shown that externally supplied retinoic acid (RA), a compound of Vitamin A, has a role in the development of the skeleton. Understanding how the mechanical properties of the meniscus and articular cartilage change with different levels of degeneration could potentially lead to the development of methods to diagnose degenerative joint disease at earlier stages. During cartilage degradation, cleavage of the proteoglycans - one of the main components of cartilage- is observed. Proteoglycans are characterized by the attachment of of glucosaminoglycan (GAG) chains. Thus, the cleavage process can be quantified by measuring the release of these GAG chains in the tissue. This research project explores the effects of RA in the degeneration of the meniscus and its mechanical properties. Fibrocartilage and articular cartilage explants from immature bovine meniscus will be harvested for this experiment.  RA will be added to a basal solution to create 0µM, 1µM and 10µM RA solutions to have three different test groups. The release of GAG in the media will be quantified with a dimethylmethylene blue (DMMB) assay. Explant material properties will be measured using oscillatory unconfined compression and torsional shear tests.