Weightlessness looks like fun but as astronauts know, prolonged exposure to zero gravity can weaken bones. Studies show that astronauts lose one to two percent of bone mass every month in space. Now, researchers are blasting mouse bone cells called osteocytes (pictured) up to the International Space Station to figure out why. Osteocytes can sense mechanical forces acting on bones, and respond by telling other bone cells to make or remove bone. The team plans to freeze the samples at various intervals to see how exposure to microgravity changes the osteocytes and the gene activity within those cells. If they can work out why bone loss happens so quickly in space it might be possible to counteract it, enabling longer space missions. But the results may also help people on Earth with osteoporosis, a condition in which bone loss makes bones fragile and prone to fracture.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.