Enhancing the effects of exfoliated carbon nanofibers using bone morphogenetic protein in a rat spinal fusion model.

Exfoliated carbon nanofibers (ExCNFs) are expected to serve as excellent scaffolds for promoting and guiding bone-tissue regeneration. We aimed to enhance the effects of ExCNFs using bone morphogenetic proteins (BMPs) and examined their feasibility and safety in clinical applications using a rat spinal fusion model. Group I (n = 15) animals were implanted with the control carrier; Group II (n = 16) animals were implanted with carrier containing 1 μg ExCNFs; Group III (n = 16) animals were implanted with carrier containing 1 μg recombinant human (rh) BMP-2; and Group IV (n = 17) animals were implanted with carrier containing 1 μg rhBMP-2 and 1 μg ExCNFs. The rats were euthanized after 4 or 8 weeks and their spines were explanted and assessed by manual palpation, radiographs, and high-resolution microcomputerized tomography (micro-CT); the spines were also subjected to histological analysis. The fusion rates in Group IV (25.0%: 4-week, 45.5%: 8-week) were considerably higher than in Groups I (0%: 4-week, 0%: 8-week), II (0%: 4-week, 15.0%: 8-week), and III (16.7%: 4-week, 30.0%: 8-week). These results demonstrated the enhancement of ExCNF bone fusion effects by BMP in a rat spinal fusion model. Our results suggest that the enhancement of ExCNFs effects by BMP makes this combination a possible attractive therapy for spinal fusion surgeries. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2892-2900, 2018.