伊班膦酸钠对糖皮质激素引起的家兔骨质量下降的预防作用

目的 探讨伊班膦酸钠在糖皮质激素引起的家兔骨质量下降的预防作用.方法 30只新西兰大白兔,随机分为对照组、模型组(肌肉注射地塞米松,3 mg/kg,2次/周,)和干预组(肌肉注射1次伊班膦酸钠2 mg/kg进行干预,肌肉注射地塞米松3 mg/kg,2次/周).6周后,第3腰椎、两侧股骨与肱骨进行骨生物力学测定,第2腰椎和右侧股骨颈苏木精-伊红(HE)染色进行形态学观察与分析.结果 与对照组相比,模型组腰椎压缩实验和股骨三点弯曲实验的最大负荷及肱骨扭转最大扭矩分别降低了27.2％、26.8％和52.0％(P＜0.01)；形态学观察骨质疏松的形态改变明显,家兔腰椎骨小梁面密度、厚度、数目分别降低了57.5％、39.2％和35.5％,分离度增加了120.8％(P＜0.01).与模型组相比,干预组骨生物力学指标分别增加了24.2％、29.9％和37.2％(P＜0.01)；形态学观察骨小梁则排列密集、连接增多、成骨活跃、腔内血细胞丰富,家兔腰椎骨小梁面密度、厚度、数目分别增加100.0％、40.6％和45.7％,分离度降低了43.9％(P＜0.01).股骨颈骨小梁形态计量学变化与腰椎骨小梁的变化相似.结论 糖皮质激素开始治疗的同时,应用伊班膦酸钠进行干预,可有效预防实验家兔骨质量的下降.

Ibandronate for prevention of glucocorticoid induced loss of bone quality in rabbits

Objective To evaluate the preventive effects of ibandronate on the glucocorticoid induced loss of bone quality in rabbits.Methods Thirty New Zealand white rabbits were randomly divided into three groups.The rabbits of model group were intramuscularly injected dexamethasone at a dose of 3 mg/kg twice weekly,the rabbits of intervention group were treated with ibandronate sodium at a dose of 2 mg/kg only once and dexamethasone at a dose of 3 mg/kg twice weekly and the rabbits of control group were treated by normal saline.After six weeks of treatment,the biomechanical characteristics were measured in both right and left sides of femora and humerus by three points bending test and torsion test,and the third lumbar spine by compression test.The morphology of the right femoral neck and the second lumbar spine were observed by HE staining under the optical microscope and analyzed by Motic Med 6.0.Results Compared with control group,the third lumbar spine and femur’s maximum load,and the humerus’ maximum torque in model group decreased by 27.2%,26.8% and 52.0%,respectively(P<0.01).At the same time,the significant morphological changes of osteoporosis were observed and the surface density of trabecular bone decreased obviously in model group.And the histomorphometric analysis of lumbar spine revealed bone volume/tissue volume(BV/TV),trabecular number(Tb.N) and trabecular thickness(Tb.Th) in group DX6 were decreased by 57.5%,35.5% and 39.3%,respectively(P<0.01);trabecular separation(Tb.Sp) was significantly increased by 120.8%(P<0.01).Compared with model group,the biomechanical parameters of intervention group increased respectively by 24.2%,29.9% and 37.2%(P<0.01).It was observed that greater number of trabecular bone concentrated and arranged regularly and lots of osteoblasts with larger cell nucleolus and rich blood cells distributed in trabecular spacing.BV/TV,Tb.N and Tb.Th of lumbar spine in intervention group were increased by 100.0%,40.6% and 45.7%,respectively(P<0.01),and Tb.Sp decreased by 43.9%(P<0.01).The histomorphometric parameters of femoral neck were similar with those of lumbar spine.Conclusion In the initiating of glucocorticoid therapy,ibandronate can effectively prevent loss of bone quality in rabbits.