Osteobiology, strain, and microgravity. Part II: Studies at the tissue level

Loading, microgravity, and/or defective mechanical strain/forces have impor tant effects on bone cells and bone quality and quantity. The complex mecha nisms induced by strain and microgravity on bone cells have been reviewed i n Part I of this paper. In Part II, we have considered the data on the alte rations induced by unloading and microgravity on the skeleton and the mecha nisms that are involved at the tissue level in animals and humans.