Bone loss, decreased bone density and de-calcification are one the major physiological weaknesses observed during long-duration spaceflight, this is mainly connected to the lack, or greatly reduced, mechanical loads exerted on bones in microgravity. However, it remains to be verified whether bone loss is due to a decreased synthesis (osteoblastic activity), or to an increased resorption (osteoclastic activity), or to both. Alterations in the proliferative answer and in the differentiation of the osteoblasts and/or osteoclasts or of their precursors (in the bone marrow) may explain the microgravity catabolic effects on bone tissue.
This experiment will assess the microgravity effects on mesenchymal Bone Marrow Stromal Cells, which contain a very active fraction of multipotents bone-cells precursors. Results may help to better understand the bone-loss in microgravity, which may be considered as an 'accelerated' experimental osteoporosis model.