Simvastatin Partially Prevents Bone Loss in Tail-suspended Rat:Bone Mineral Density and Histomorphometry Analysis

Background: Skeletal unloading induces osteopenia in the loaded bones.Simvastatin, as one of the HMG-CoA reductase inhibitors for lowering lipids, has been demonstrated its potential benefit in bone formation, while no study reported whether simvastatin could prevent the bone loss in unloaded bone.Objective: We performed this study to assess the effect of simvastatin on bone mass and bone formation in tail-suspension rat.Methods: Tailsuspension rats were treated with or without simvastatin for 3 weeks, The right femurs were removed for the measurement of bone histomorphometry after bone mineral density(BMD) assessment by dual-energy X-ray absorptiometry.Results: The total bone mineral density(tBMD) and distal bone mineral density(dBMD) of tailsuspended rats were significantly lower than that of normal rat, while proximal bone mineral density(pBMD) of normal rats was significantly higher than tail-suspended rat, but no statistical difference was observed between normal and simvastatin-treatment rats.Similar to the BMD results, histomorphometric assessment for the trabeculae bone of distal femurs showed markedly higher BV/TV and lower trabecular Tb.Sp in normal rats compared to those of tailsuspended rats, while both the bone formation and bone resorption parameters were markedly increased in tail-suspended rats with or without simvastatin treatment, simvastatin showed stimulation on osteoid formation comparing to normal and tail-suspended rats.Conclusion: simvastatin treatment could partially prevent tailsuspention-induced osteoporosis in unloaded limb.