泼尼松对大鼠股骨和腰椎骨密度和力学性能影响的实验研究

摘要

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.%目的探讨泼尼松对大鼠股骨和腰椎的骨密度和生物力学性能影响.方法21只3月龄雄性SD大鼠,体质量(226±12)g,随机分为基础对照组、年龄对照组、激素造模组.激素造模组喂醋酸泼尼松4.5 mg@kg-1,每周2次.3个月后,用双能X线吸收骨密度测量扫描仪(DEXA)对各组的离体双侧股骨和第5腰椎进行骨密度测定,然后用SWD-10型材料试验机行股骨干的扭转、三点弯曲和腰椎的压缩试验.结果年龄对照组和激素造模组体质量分别为(28l±18)g和(269±19)g,两组之间比较无显著性差异(提示本实验中醋酸泼尼松的用量对动物无明显毒性).激素造模组与年龄对照组比较,股骨、腰椎总骨密度减少了14.64%(P<0.01);右、左股骨远段和腰椎的骨密度分别减少了21.42%(P<0.01)、19.62%(P<0.05)和23.48%(P<0.01),其余节段的骨密度均有所减少.与年龄对照组比较,激素造模组股骨三点弯曲的载荷减少了17.1%(P<0.05),其余的力学参数都有减少的趋势.结论长期使用皮质类固醇,会使大鼠的骨密度减少和力学性能下降,其中松质骨的丢失比皮质骨更为明显,故患骨质疏松时松质骨更容易发生骨折.