Effects of prednisone on bone mineral density and biomechanical characteristics of the femora and lumbar vertebras in rats

doi:10.3321/j.issn:1673-4254.2003.02.001

Abstract：Objective To explore effects ofprednisone on the bone mineral density (BMD) and biomechanics of the femoraand lumbar vertebras in rats. Methods Twenty one 3-month-old male Sprague-Dawley rats weighing 226+12 g were randomlydivided into basal control, age-matched and hormone groups. The rats in basal control group were killed at the beginning ofthe experiment without any treatment, and those in age-matched group were given oral normal saline (5 ml@ kg4@ d-1) while therats in hormone group received oral prednisone acetate (4.5 ml@ kg-1@ d-1 twice a week) to establish osteoporotic models. Thetreatment for the latter 2 groups of rats lasted for 90 days, after which the BMD and mechanical measurements of the femursand L5 vertebra were carded out by way of torsion, three-point bending and compression tests. The measurements were alsoconducted in the basal control group at the time indicated above. Results In hormone group, the total BMD of the femora andL5 vertebra was decreased by 14.64%(P＜0.01), and the BMD in the right and left distal femoral segments and the vertebradecreased by 21.42% (P＜0.01), 19.62% (P＜0.05) and 23.48%(P＜0.01), respectively, in comparison with the control group. Inthe meantime, the loads of three-point bending test in hormone group was decreased by 17.1%(P＜0.05), whereas the restparameters tended to decrease as compared with the control group. Conclusions Chronic use of corticosteroid is more liable tocause bone mass loss in rat cancellous bone than in the cortical bone, and mechanical properties of the cortical and cancellousbone, especially those of the latter, will also decline, to give rise to easy bone fracture at the trabecular bone in osteoporoticconditions.