Osteoarthritis is a degenerative disease mainly caused by aging, although in younger patients (aged 25 – 50) it can be a consequence of sports-related injuries or trauma. This results in early osteoarthritis with subsequent changes in cartilage extracellular matrix. Cell-based tissue engineering approaches using mesenchymal stem cells (MSCs) are an ideal cell type for the treatment of early osteoarthritc defects. Our group has demonstrated in a clinical study, that interleukin-1β (IL-1β) was expressed in cartilage plugs from patients with early osteoarthritis. In vitro studies have shown that IL-1β inhibits cartilage formation in chondrocytes or MSCs undergoing chondrogenesis. However, these studies show complete inhibition of tissue formation, whereas in the context of early osteoarthritis, cartilage extracellular matrix remains around the defect site. Thus, the present study sought to develop a model mimicking early osteoarthritis using MSCs.

Osteoarthritis is a degenerative disease that results in changes in cartilage extracellular matrix. In vitro studies have shown that IL-1β inhibits cartilage formation in chondrocytes or MSCs undergoing chondrogenesis. In vivo, articular chondrocytes and bone marrow reside under hypoxic or physioxic environment (1–5% oxygen) and previous investigations have shown an increase in cartilage matrix proteins and reduced hypertrophy for MSC chondrogenesis, especially for MSCs expanded and differentiated under physioxia. Our hypothesis was that physioxic preconditioning reduces the effects of IL-1β inhibited MSC chondrogenesis.