Abstract
Mechanical loading provides indispensible stimuli for growth and development of the articular cartilage and bone. Interestingly, depending on loading conditions loads applied to the joint can be beneficial as well as harmful to skeletal maintenance and remodeling. Moderate loads to the synovial joint, for instance, suppress the expression levels of matrix metallproteinases (MMPs), while loads above a threshold tend to increase their destructive activities. This report focuses on two recently developed loading modalities from animal studies, joint motion and joint loading. Their unique characteristics and potential usages for maintenance of the articular cartilage and stimulation of bone remodeling are reviewed. Also described are biophysical and molecular mechanisms which likely are responsible for the load-driven maintenance of cartilage and bone, and a possibility of developing load-mediated treatments of osteoporosis and osteoarthritis.