Effects of Zoledronic Acid on Bone Structure and Organization of Nanocomposites in Rats with Glucocorticoid-Induced Osteoporosis

Abstract

Continuous use of methylprednisolone (Mps) is one of the most common causes of secondary osteoporosis resulting in alterations of the skeleton microstructure and increased fracture risk. The aim of the research was to assess the influence of zoledronic acid on mineral mass, micro- and nanostructure of the bones in rats, which received glucocorticoids. Wistar rats were randomly divided into three groups: vehicle control, the introduction of methylprednisolone, 3 mg/kg/day (Mps), and Mps combined with zoledronic acid, 0.025 mg/kg (Mps+Zol.). The relative amount of a crystalline component and collagen in the bones was detected by means of X-ray diffraction, microstructure, and calcium level through atomic absorption spectroscopy. Methylprednisolone caused a decrease in the amount of a mineral component in the femoral neck (to -39.8%) in group Mps than vehicle control. It should be emphasized that the introduction of Zol. did not allow a significant decrease in a mineral component of the bone during the experiment (-11.7% on the 24th day) compared with Mps group, and indices were almost at the same level as in the control group. Zoledronic acid can partially inhibit harmful consequences of glucocorticoids for bone structure in rats and improve mineralization without impairment of crystal parameters of hydroxyapatite lattice.