Opinion Statement of the Effect of Mechanical Stress on Cartilage Tissue Engineering

Articular cartilage is characterized by its poor capacity for self-repair. Once articular cartilage is injured and defected, it cannot be spontaneously repaired and finally develops osteoarthritis (OA). OA is a major leading cause of severe activity limitations and disability, resulting in worldwide socio-economical burden. At present, there is no established therapy for adequate repair of damaged articular cartilage. Researchers have therefore attempted to establish the cartilage tissue engineering as an effective alternative treatment of cartilage repair. However, the articular cartilage repair still remains a clinical and scientific challenge. In cartilage tissue engineering, it is believed that cell source, scaffold and growth factors are three key factors for the desired result of cell therapy for the damaged cartilage repair. However, increasing evidence is showing that these key factors are not enough and other factors may be required to achieve the optimal outcome. Since normal articular cartilage is always subjected to mechanical stress in daily activities, mechanical stress has attracted much attention as fourth key factor in cartilage tissue engineering. However, the real impact of mechanical stress on cartilage tissue engineering is far from complete understanding. In this review, we summarize the accumulating knowledge of the effect of mechanical stress on cartilage tissue engineering and discuss about the challenges for the future.