Evaluation of radiographic density and proportion of trabecular bone in the femur of female rats medicated with glucocorticoid and bisphosphonate Avaliação da densidade radiográfica e da proporção trabecular do fêmur de ratas medicadas com glicocorticóide e bisfosfonato

Purpose: To evaluate the radiographic density and proportion of trabecular bone in the femur of female rats treated with glucocorticoid combined or not with bisphosphonate. Methods: Thirty-six female Wistar rats were allocated to 3 groups: (1) control, (2) glucocorticoid, and (3) glucocorticoid + bisphosphonate. Group 1 was given saline solution (subcutaneous injections – 2 mL/kg), groups 2 and 3 were given methylprednisolone acetate (1 mg/kg). Group 3 also received risedronate (3 mg/kg). The animals were killed and each left femur was dissected, radiographed, and histologically processed. A single observer, blind to experimental group, measured optical density and the proportion of trabecular bone. Data were analyzed using ANOVA and Tukey test (α=5 %). Results: Radiographic density was lower in group 2 than in groups 1 and 3, which were not statistically different. Group 2 had a lower mean proportion of trabecular bone than group 3; groups 2 and 3 did not differ from group 1. Conclusions: These results suggest that administration of bisphosphonate reverses reduction in the proportion of trabecular bone resulting from glucocorticoid use, and that it is possible