[Effect of cyclophosphamide on bone remodeling in rats]

Neoplasms, with or without metastases in bones, can induce pathological bone remodeling, leading to systemic bone resorption and hypercalcemia or osteomalacia and normocalcemia. The aim of the present study was to investigate the effect of a cytostatic--cyclophosphamide on the skeletal system in rats. The experiments were carried out in male Wistar rats with initial body weight of 212-229 g, divided into 3 groups (n = 6): I--Control, II--Cyclophosphamide (10 mg/kg m.c. i.m. daily for 14 days, and after a 7-day break, for 7 days), III--Cyclophosphamide (20 mg/kg m.c.p.o. daily for the initial 14 days). After 30 days of the experiment, the animals were killed and bone mass, length and diameter of long bones, mineral content in bones, transverse cross-section surfaces of the cortical diaphysis and of the marrow cavity, transverse growth, width of endosteal and periosteal osteoid in the tibia, width of trabeculae, width of epiphyseal cartilage and mechanical features of the femur were examined. Cyclophosphamide caused disorders of bone tissue remodeling. Decreases in bone mass, length, diameter, mineral content in bones, width of trabeculae in the femur, transverse growth, width of osteoid, transverse cross-section surface of the cortical diaphysis, and worsening of mechanical properties of the femur were observed.