RESUMO
PURPOSE: To study the effect of a long-term, oral, fixed dose with a combination of alendronate and calcitriol on the cancellous bone microarchitecture in an ovariectomized rat model. MATERIALS AND METHODS: Twenty eight female Sprague-Dawley rats were divided into 2 equal groups: a non-medication group (OVX), and a medication group (ALD). The ALD group was treated with an oral daily fixed dose with a combination of alendronate and calcitriol for six months, starting from 4 weeks after ovariectomy, while the OVX group was given only a placebo. After six months, all animals were sacrificed, and an in vitro micro-CT analysis of the the distal femur was performed. The bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular number (Tb.N), structure model index (SMI), connectivity density (Conn.D), and bone mineral density (BMD) were assessed. RESULTS: The ALD group had significantly higher BV/TV, Tb N, BMD and Conn.D and it also had significantly lower Tb Sp and SMI than the OVX group. CONCLUSION: A long term, daily, oral fixed dose with a combination of alendronate and calcitriol could significantly reduce the osteoporotic changes in this ovariectomized rat model.