泼尼松对Ⅱ型胶原诱导性关节炎大鼠股骨微结构及生物力学的影响

Effects of prednisone on trabecular microstructure and biomechanical properties of femur in a rat model of type II collagen-induced arthritis

目的应用骨生物力学和micro-CT技术,探讨泼尼松对Ⅱ型胶原诱导性关节炎(CIA)大鼠股骨微结构及生物力学的影响。方法 40只8周龄Lewis♂大鼠,随机分为正常对照(CON)组6只、其余34只用来建立CIA模型。免疫3周后筛选出CIA大鼠随机分成CIA组、CIA加泼尼松4.5mg·kg-1·d-1组和CIA加泼尼松9 mg·kg-1·d-1组。CON和CIA组给予溶剂对照溶液,其它2组给予泼尼松4.5、9 mg·kg-1·d-1。连续给药90 d后处死,取左股骨进行生物力学测定,然后进行micro-CT扫描及三维重建。结果与CON组比较,CIA组骨小梁厚度、骨小梁数量、骨体积分数、骨密度明显减小,而骨小梁分离度、结构模型指数明显增加,骨生物力学参数(弹性载荷、最大载荷、断裂载荷、刚度)均明显减小。与CIA组比较,泼尼松2个剂量组骨体积分数与骨小梁数量均增加,骨小梁分离度均减小,而骨生物力学参数均无明显变化。结论泼尼松治疗CIA大鼠3个月后,对股骨松质骨微结构破坏有所改善,但对股骨生物力学性能和骨密度没有明显改变。

Aim To investigate the effects of predni-sone on trabecular microstructure and biomechanical properties of femur in a rat model of type II collagen-induced arthritis （CIA ） using micro-CT and biome-chanics.Methods Forty 8-week-old male Lewis rats were randomly divided into 2 groups：control （CON ） group with 6 rats,and the remaining 34 rats were used to establish the CIA model.3 weeks after immunization screening CIA rats were randomly divided into CIA group,CIA plus prednisone 4.5 mg · kg-1 · d -1 group and CIA plus prednisone 9 mg · kg-1 · d -1 group.Rats in CON group were given vehicle as well as in CIA group.Rats in the other two groups were treated with prednisone at 4.5 mg·kg-1 ·d -1 or 9 mg ·kg-1 · d -1 .After 90 days treatment,all rats were euthanized,and the left femur was collected for biome-chanics,micro-CT scanning and three-dimensional re-construction.Results Micro-CT data showed that tra-becular thickness,trabecular number,bone volume/total volume,bone mineral density in CIA group were significantly lower than those in CON group.While tra-becular separation,structure model index were signifi-cantly higher than those in CON group.Compared with CON group,biomechanical properties （elastic load, maximum load,break load and stiffness）were signifi-cantly decreased in CIA group.Compared with CIA group,bone volume/total volume and trabecular num-ber were increased,while trabecular separation was significantly decreased in two prednisone groups.Com-pared with CIA group,there was no significant change in biomechanical properties in two prednisone groups. Conclusions Treatment with prednisone for 3 months can ameliorate the damage of trabecular microstructure of the femur in CIA rats,but it has no effect on biome-chanical properties and bone mineral density.