Daily or monthly ibandronate prevents or restores deteriorations of bone mass, architecture, biomechanical properties and markers of bone turnover in androgen-deficient aged rats.

ABSTRACT

AIM: The aim of this study was to investigate the effects of the bisphosphonate ibandronate (IBN) in a male osteoporosis animal model. METHODS: Two studies were performed in 9-month-old orchidectomised (ORX) or sham-operated rats. In prevention study, subcutaneous IBN was administered daily (1 µg/kg) or monthly (28 µg/kg every 28 days) starting on day of surgery for 5 months. In treatment study, the same treatment started 6 months after ORX. After sacrifice, bone analyses by dual-energy X-ray absorptiometry, 3-dimensional micro-computed tomography, and 3-point bending were performed in femora or vertebrae. Serum tartrate-resistant acid phosphatase 5b (TRAP-5b) and aminoterminal propeptide of collagen I (PINP) were analysed for resorption and osteocalcin (BGP) for bone formation. RESULTS: In both studies, ORX resulted in significant femoral and vertebral bone loss and microarchitectural deterioration after 5 months of ORX, and became more pronounced after 11 months. Biomechanical strength was also decreased. Serum levels for TRAP-5b and BGP increased while PINP levels were reduced or unchanged. Both daily and monthly IBN prevented or even restored ORX-induced changes in both studies, with the intermittent regimen showing a improvement in efficacy with respect to many of the biomechanical parameters.