Estrogen reduces mechanical injury-related cell death and proteoglycan degradation in mature articular cartilage independent of the presence of the superficial zone tissue

E2 prevents injury-related cell death and GAG release, and might be useful for the development of treatment options for either cartilage-related sports injuries or osteoarthritis (OA). The SFZ does not seem to play an important role in (1) the E2-related tissue response and (2) the mechanically-induced cell death in deeper regions of the explants and GAG release. The latter might be related to the unconfined nature of the injury model.