Influence of prednisolone on craniofacial and long bones in growing rats: A cephalometric and peripheral quantitative computed tomographic analysis

Glucocorticoids are used for treatment of a variety of diseases, although they are also known to have an effect on skeletal growth and induce osteoporosis. The aim of this study was to investigate whether exposure to prednisolone had an effect on craniofacial bone growth and the internal bone structure in young rats. Twenty 5-week-old growing male rats were divided into two equal groups. Prednisolone at 30 mg/kg/day (prednisolone group) or no drug (control group) was administered orally on alternate days for 6 weeks. Thereafter, growth of the total skull, neurocranium, maxilla, and mandible was determined on lateral cephalograms, while cortical bone density and strength strain index (SSI) of the femur diaphysis and mandible were determined using peripheral quantitative computed tomography (pQCT). In addition, the femur length was measured. In the prednisolone group, total body weight, femur length, mandibular corpus length and height, and coronoid process height were reduced. No effects of prednisolone administration on cortical bone density of the femur and mandible were detected, however, the SSI values, cortical bone cross-sectional area, and mineral content of the femur and mandible, and cortical thickness and periosteal circumference of the femur in the prednisolone group were significantly lower when compared with the control group. The findings indicate that glucocorticoid administration decreases longitudinal and mandibular bone growth, quality, and strength in growing rats, whereas it has no significant effect on cortical bone density.