Evaluation of radiographic density and proportion of trabecular bone in the femur of female rats medicated with glucocorticoid and bisphosphonate

Abstract

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 to detect these changes with radiography. Key words: Osteoporosis; rats; femur; radiography; histomorphometry