Introduction: Osteoporosis is the most prevalent bone disease in humans, affecting people of all ages but more common in postmenopausal women. Risedronate (RIS) and strontium ranelate (SR) are two clinically accessible anti-osteoporotic medicines.
Objectives: To assess and compare the anti-osteoporotic effects of RIS and SR on the histologic, histomorphometric, and ultrastructural features of compact bones in a rat model of glucocorticoid-induced osteoporosis.
Materials and Methods: 42 mature healthy male albino rats were randomly allocated into 6 main groups (7 rats /group) and received daily oral treatments for 12 weeks as following: negative control, RIS +ve control (2.5 mg/kg/day), SR +ve control (625 mg/kg/day), prednisolone (pred)-treated (1.5 mg/kg/day), pred + RIS (treated concurrently with prednisolone and RIS), and pred + SR (treated concurrently with prednisolone and SR). At the end of the experiment, all animals were anesthetized, sacrificed, and the femurs and tibias were excised for x-ray, histological, histomorphometric, and electron microscopic studies.
Results: Oral prednisolone provoked significant osteoporotic changes as evidenced by generalized osteopenia and bone bending detected in the X-ray. Histological examination demonstrated decreased cortical bone thickness, multiple irregular perforations, reduced lamellar bone formation, and an increase in the osteoid tissue. Ultrastructural changes were observed in the form of distorted osteoblasts and osteocytes together with lysis of collagen fibrils in the bone matrix. Oral administration of RIS and SR was associated with moderate and marked improvement of prednisolone induced perturbations of the bone architecture respectively.
Conclusion: Our data suggest that SR outperforms RIS in alleviating glucocorticoid-induced osteoporotic changes in cortical bone tissues.