Architectural and mechanical properties of cancellous bone with strontium treatment in osteoporotic goats

Abstract

INTRODUCTION: Recently, strontium (Sr) compounds have become more popular in the treatment of osteoporosis by concomitantly inhibiting bone resorption and enhancing bone formation. Previously, we developed a novel strontium fortified calcium compound. This study was designed to evaluate the effects of this compound on the micro-architectural and nano-mechanical properties of cancellous bone in osteoporotic goats. MATERIALS AND METHODS: Large animal model of osteoporosis was established in aged goats underwent ovariectomy. Strontium fortified calcium compound were orally administered for 4 months. Histomorphometric indices were determined and trabecular micro-architectural parameters from µCT were quantified. The biomechanical properties of single trabecula were determined by nano-indentation. RESULTS AND DISCUSSION: Sr combined with Ca treatment increased osteoid area and the anabolic effects of Sr were confirmed from the increased bone mineral apposition rate. No adverse effects on bone mineralization were detected. Consistent with histomorphometric indices, µCT results demonstrated that combination treatment increased bone mineral density. Sr combined with Ca treatment significantly increased trabecular bone volume by 12.22%, primarily by increasing trabecular thickness (Tb.Th*). Elastic modulus (E) of single trabecula was not changed in Sr combined with Ca treatment despite a slight decrease in hardness (H). This results in considerable increase in fracture toughness of bone and contributes as one of the reasons for fracture risks reduction in postmenopausal women after Sr treatment. CONCLUSION: The present results indicate that Sr combined with Ca increased bone volume by stimulating new bone formation, thus increased the toughness of bone and decreased the fracture risk.