TGFbeta3 and loading increases osteocyte survival in human cancellous bone cultured ex vivo

The goal of this study was to assess the effect of the addition of TGFbeta(3), alone or in combination with loading, on the survival of osteocytes in 3D human explant cancellous bone during long-term culture in an ex vivo loading bioreactor. Human cancellous bone explants were cultured for up to 14 days with or without TGFbeta(3) (15 ng ml(-1)) and with or without loading (300 cycles, at 1 Hz, producing 4000 microstrain). Bone core response was visualized using undecalcified histology with morphological methods after embedding with Technovit 9100 New resin. Histological examination revealed normal gross level bone structure with or without the application of load or the addition of TGFbeta(3). The viability of the osteocytes within the bone was assessed by lactate dehydrogenase (LDH) activity. We demonstrate that this ex vivo loading bioreactor is able to maintain a high percentage (over 50%) of viable osteocytes throughout the bone explants after 14 days in ex vivo culture. Further to this, the combination of daily loading and TGFbeta(3) administration produced superior osteocyte survival at the core centres when compared to loading or TGFbeta alone.