糖皮质激素性骨质疏松模型兔的建立与3.0T磁共振波谱评价

摘要

目的 3.0T 磁共振波谱(MRS)评估糖皮质激素性骨质疏松(GIOP)模型兔的可行性.方法 19只20周龄雌性新西兰大白兔随机分为对照组(n=9)及肌注甲泼尼龙琥珀酸钠组(MPS组,n=10).分别在基线、4周、8周行股骨近端及L3～L4骨密度扫描及MRS扫描获取骨髓脂肪分数(FF).结果 第4周时,MPS组FF(42.4%±6.3%)较对照组(32.5%±6.5%)显著增高(P=0.003),而组间骨密度无统计学差异.第8周时,MPS组股骨近端及L3～L4骨密度都较对照组明显降低(P均＜0.001).第4、8周时MPS组FF较基线时分别增高36.3%、60.5%,而股骨近端与L3～L4骨密度分别较基线时降低4.5%、13.3%与6.5%、14.4%.结论 GIOP模型兔可在8周内建立,MRS是该模型的有效评估方法之一.%Objective To clarify the feasibility of evaluating the glucocorticoid-induced osteoporosis( GIOP) in rabbits with MR spectroscopy. Methods Nineteen female New Zealand white rabbits ( 20-week-old ) were randomly assigned to two groups: MPS group (n= 10) received subcutaneous injections of MPS for the first 4 weeks at a dose of 1. 5 mg/kg everyday, and then at a dose of 0. 35 mg/kg (three times per week) for another 4 weeks. The control group (n =9) received subcutaneous injections of normal saline according to the same schedule. The animals were subjected to the same MR protocol and dual energy X-ray absorptiomctry scanning at 4 and 8 weeks after baseline imaging. Results There was a significant increase of bone marrow fat fraction (FF) in MPS group (42. 4 % ± 6. 3 % ) compared with control group (32. 5 % ± 6. 5 % ) (P = 0. 003 ) , but no significant differences in both proximal femur BMD and L3 - L4 bone mineral density (BMD) were detected at week 4. At week 8, both proximal femur BMD and L3 - L4 BMD of MPS group were significantly lower (P<0. 001 for all) than those of control group. In comparison with baseline, FF values in MPS group increased by 36. 3% and 60. 5% at 4 , 8 weeks respectively, while proximal femur BMD and L3 - L4 BMD decreased by 4.5% and 13. 3% , 6. 5% and 14. A%. Conclusion GIOP in rabbits can be induced successfully in eight weeks. MRS may be valuable in the early, non-invasive evaluation of a rabbit osteoporosis model.