Strontium ranelate is a drug that has promising effects on the treatment of women with post-menopausal osteoporosis. An advantage of this drug compared to others is its unique effect on bone cells: it simultaneously promotes bone formation by osteoblasts and inhibits bone resorption by osteoclasts. However, its effects on the mineralised bone matrix are not yet fully known. In particular, due to the presence of strontium ions (Sr2+) in its composition, this drug could lead to several changes in the bone mineral phase, which must be evaluated. Besides the treatment of osteoporosis, strontium ranelate was also shown to increase the osseointegration of bone implants in animals. The better understanding of how the drug promotes this effect, and mainly of its actions on the cellular component of the bone/implant interaction, may contribute to its possible application aiming to increase the clinical success of bone implants. The main goal of this study was to evaluate effects of strontium ranelate on bone mineralisation and on the interaction of osteoblasts with titanium surfaces. In particular, we evaluated, in osteoblast cultures treated with strontium ranelate: (1) the formation and nature of the mineralised matrix; (2) the composition and crystal structure of the mineral phase; and (3) the cell behaviour and matrix formation on titanium surfaces. As main results, we noticed that strontium ranelate: (1) promotes bone mineralisation preserving the overall nature of the matrix; (2) leads to several changes in intrinsic properties of the mineral phase, such as: substitution of slightly less than 10% of Ca2+ by Sr2+ in the apatite crystal lattice, increase in the lattice parameters a and c, increase in the type-B CO32- content, and changes in PO43- environments; and (3) has positive effects on the interaction of osteoblasts with titanium surfaces, including in cell proliferation, differentiation, and formation of bone-like matrix.
Disclosure: The authors declared no competing interests. This study was supported by FAPERJ and CNPq (Brazil) and by the CAPES/COFECUB program n° 628/09 (Brazil/France cooperation).