[Effects of amsacrine and cytarabine on bones in rats]

Development of neoplastic diseases can lead to various metabolic changes in the bone tissue. The aim of the present study was to investigate effects of two antineoplastic agents: amsacrine and cytarabine on the bone system in rats. The experiments were carried out on male Wistar rats (initial body mass: 115-150 g). Amsacrine or cytarabine were administered subcutaneously in a dose of 3 mg/kg daily for four weeks. Cytarabine was administered every day, whereas amsacrine was administered every day for the first 7 days and then, after a five-day break, every second day up to the end of the experiment. The results were compared with those of appropriate control groups. Bone mass, length, diameter, mineral and calcium content, incorporation and release of 45Ca+2 in bones, transverse growth, width of endosteal and periosteal osteoid, transverse cross-section area of the cortical part of the diaphysis and of the marrow cavity in the tibia, width of epiphyseal cartilage, width of trabeculae and mechanical properties in the femur were examined. Administration of amsacrine caused osteopenic changes in rat bones, with decreases in bone mass, mineral content, longitudinal and transverse growth of the long bones, width of endosteal and periosteal osteoid, transverse cross-section area of the cortical part of the tibial diaphysis, width of trabeculae and width of epiphyseal cartilage. Disorders in the calcium metabolism in the bone tissue (decreases in the incorporation and release of 45Ca+2 in bones) and worsening of mechanical properties of the long bones were observed. After administration of cytarabine, the damages to processes of bone tissue remodeling were much lesser. Decreases in bone mass, bone mineral content and incorporation and release of 45Ca+2 were observed.