ABSTRACT
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.