Experimental Intervertebral Disc Regeneration with Tissue-Engineered Composite in a Canine Model

The aims of this study were to construct the composite of poly (L-lactic-co-glycolic acid) (PLGA) scaffold-nucleus pulposus (NP) cells using tissue engineering methods and to investigate the in vivo performance of the composite in a canine model. NP cells were isolated from the lumbar intervertebral discs of a beagle dog. NP cells were cultured, expanded in vitro, and seeded onto a three-dimensional porous PLGA scaffold. The composite was tested in 18 beagle dogs that were randomly divided into three groups: nucleotomy alone (A), nucleotomy with PLGA implantation (B), and nucleotomy with PLGA scaffold/NP cells composite implantation (C). X-ray and magnetic resonance imaging were performed pre- and postoperatively. Evaluation of disc height, segment stability, and biomechanics and immunohistochemical analysis were performed. Dog NP cells attached and showed proliferation activity within the PLGA scaffold in vitro and in vivo. Disc height, segmental stability, and T2-weighted signal intensity on magnetic resonance imaging scans were well preserved in group C dogs with the engineered composite. PHK-26-positive cells were found within the area of the NP 8 weeks postoperatively. The NP cell-PLGA scaffold composite can prevent or delay the degeneration process after nucleotomy in the canine model. This hybrid composite might be a promising construct for intervertebral disc regeneration.