effects of vitamin d and calcium supplementation on micro-architectural and densitometric changes of rat femur in a microgravity simulator model

background: revealing data on the role of vitamin d and calcium supplementation in bone health has led some to suggest that vitamin d and calcium treatment could also play a role in protecting bone against microgravity-induced mineral loss. objectives: the aim of the present study was to investigate the effects of vitamin d and calcium administration on microscopic and densitometric changes of rat femur in a microgravity simulator model. materials and methods: after designing a microgravity simulator model, 14 rats were placed in the cages as follows: seven rats as osteoporosis group and seven rats received oral supplement of calcium/vitamin d as the treatment group. animals were sacrificed after eight weeks and then both femurs were removed. bone mineral density was measured for one femur from each animal, and morphologic studies were evaluated for the contralateral femur. results: bone mineral density of the whole femur in the treatment group was significantly higher than the osteoporosis group (0.168 ± 0.005 vs. 0.153 ± 0.006, p = 0.003). also, bone mineral content of the whole femur was significantly higher in treatment group (0.415 ± 0.016 vs. 0.372 ± 0.019, p = 0.003). however, resorption eroded surface percentage was higher in the osteoporosis group (18.86 ± 3.71% vs. 9.71 ± 1.61%, p = 0.002). conclusions: according to the results of this study, vitamin d and calcium administration might have protective effects against microgravity-induced mineral loss in a rat microgravity simulator model.