Bone Abstracts

Hydroxyapatite (HA) has been widely used as a biocompatible ceramic in many areas of medicine, mainly for contact with bone tissue, due to its resemblance to mineral bone. Owing to the nanofeatures of bone tissue, new nano-HA based materials are among the most promising challenges in bioactive ceramics. Recently, it was observed that fluoroquinolones have the ability to interfere with osteoclastogenesis, in standard polystyrene cell culture plates. The aim of this work is to assess the osteoclastogenic-modulation properties of different fluoroquinolones in cell cultures performed over HA surfaces with nano- and micro-structured topography (nHA and mHA respectively).

The sinterization temperature used was 830 °C (nHA) and 1300 °C (mHA). The HA disks were analysed by scanning electron microscopy (SEM). Osteoclastic precursor cells were isolated from human peripheral blood. Cells were seeded over HA disks. Cell cultures, maintained for 21 days in the presence of M-CSF and RANKL and treated with 0.3×10⁻⁹–0.3×10⁻³ M norfloxacin, ciprofloxacin and levofloxacin, were characterized for total protein content, cellular morphology, presence of cells with actin rings and expressing vitronectin and calcitonin receptor, TRAP activity and HA resorption ability. In addition, the involvement of some osteoclastogenic-associated signalling pathways on the observed cellular response was also addressed.

The osteoclastogenic behaviour of cell cultures was modulated by the HA surface, with a high osteoclast differentiation degree being observed over mHA disks. The presence of the tested fluoroquinolones was able to elicit changes in the cellular response. Namely, in all tested conditions, the osteoclastic response was either increased or not affected by these molecules. The relative contribution of the analysed signalling pathways was also modulated by fluoroquinolones.

In conclusion, the present work may contribute to a better understanding of the potential effects of fluoroquinolones on bone tissue, particularly in contexts where it is important to ensure proper bone tissue regeneration.