The potential of DBP gels containing intervertebral disc cells for annulus fibrosus supplementation: in vivo

Demineralized bone particle (DBP), which is widely used as a biomaterial in the ␣eld of tissue engineering, contains various bioactive molecules, such as cytokines. For this reason, in this study we  investigated the effects of injectable DBP gels on cell proliferation, in␣ammation and maintenance of  the shape of DBP gels as a scaffold able to substitute for intervertebral discs (IVDs) in vivo. DBP gels were fabricated with different percentages (5% and 10%) of DBP powder and 3% acetic acid, including 0.02% pepsin. DBP gels with annulus brosus (AF) cells were implanted into the dorsal subcutaneous region of BALB/C-nu mice for 1, 2 and 3 weeks. Cell proliferation was measured by MTT assay. The effect of DBP gels on the in␣ammatory response was analysed by measuring the amount of tumour necrosis factor-alpha (TNFa) released. Also, histological methods were carried out to analyse the response of  DBP gels in vivo. This study demonstrated that injectable DBP gels are able to provide physical scaffolds  for growing IVD cells in vivo. Copyright © 2013 John Wiley & Sons, Ltd.