Histomorphometric study of tibia of rats exposed aboard American Spacelab Life Sciences 2 Shuttle Mission

Tibial bones of rats flown onboard the SLS-2 shuttle mission were studied. Trabecular bone parameters were investigated, including growth plate height, trabecular bone volume, thickness and number, and trabecular separation in the primary and secondary spongiosa. Several histomorphometric changes were noted, allowing researchers to conclude that exposure to microgravity resulted in osteopenia of spongy bone of tibial metaphysis. The roles of bone formation and bone resorption are discussed.