| [ Summary ] |
Skeletal loading is a critical factor for maintaining normal bone tissue homeostasis. Under mechanical unloading conditions such as spaceflight and long-bed rest, bone mass decreases dramatically owing to enhanced osteoclastic bone destruction, leading to osteoporosis, a bone disease with a high risk of bone fracture. In this article, mechanisms of bone loss induced by the mechanical unloading are summarized and discussed by focusing on the bone-degrading osteoclasts and their differentiation factor RANKL. The elucidation of molecular mechanisms will not only contribute to pathological understanding but also to the development of a novel therapeutic strategy for disuse osteoporosis. |