Regulation of osteoblast differentiation by acid-etched and/or grit-blasted titanium substrate topography is enhanced by 1,25(OH)₂D₃ in a Sex-Dependent Manner

This study assessed contributions of micron-scale topography on clinically relevant titanium (Ti) to differentiation of osteoprogenitor cells and osteoblasts; the interaction of this effect with 1α,25-dihydroxyvitamin D₃(1α,25(OH)₂D₃); and if the effects are sex-dependent. Male and female rat bone marrow cells (BMCs) were cultured on acid-etched (A, Ra=0.87 μm), grit-blasted (GB, Ra=3.90 μm), or grit-blasted/acid-etched (SLA, Ra=3.22 μm) Ti. BMCs were sensitive to surface topography and underwent osteoblast differentiation. This was greatest on SLA; acid etching and grit blasting contributed additively. Primary osteoblasts were also sensitive to SLA, with less effect from individual structural components, demonstrated by enhanced local factor production. Sex-dependent responses of BMCs to topography varied with parameter whereas male and female osteoblasts responded similarly to surface treatment. 1α,25(OH)₂D₃ enhanced cell responses on all surfaces similarly. Effects were sex-dependent and male cells grown on a complex microstructured surface were much more sensitive than female cells. These results indicate that effects of the complex SLA topography are greater than acid etching or grit blasting alone on multipotent BMCs and committed osteoblasts and that individual parameters are sex-specific. The effect of 1α,25(OH)₂D₃was sex dependent. The results also suggest that levels of 1α,25(OH)₂D₃ in the patient may be important in osseointegration.