Abstract
Abstract
Long‐term space travel (e.g. travel to Mars) will greatly exceed the recommended lifetime radiation dose of 600 millisieverts (mSv) and have a detrimental effect on skeletal fragility. Our objective was to determine if 1 Gray (GY) radiation impacts the biomechanical properties of the tibia and femur from rats under microgravity. Hindlimb‐suspended male Sprague–Dawley rats were irradiated (IR) with 1 GY (+IR) or used as control (−IR); after 4 weeks they were sacrificed to obtain the femur and tibia. Using the three‐point bending technique, we found radiation had no effect on the flexure force/bending and stiffness of the femur. However, the tibias from the +IR rats demonstrated 37% less flexure force/bending and stiffness than −IR rats. Bone elemental analysis was determined using a scanning electron microscope equipped with energy dispersive spectroscopy; there was no difference in the calcium/phosphorus ratio between +IR and −IR groups. This study provides pilot data which suggest that low dose radiation exposure has a greater impact on the smaller hindlimb bones from hindlimb‐suspended rats.