title: [Bone inductive effects of rhBMP-2 loaded porous CPC implants on spine fusion in rabbits].
abstract: OBJECTIVE
  To investigate the effect of rhBMP-2 combined with porous CPC on spine fusion in rabbits.
  
  
  METHODS
  rhBMP-2 (1 mg) was loaded with 1 g CPC and 6.0 cm x 2.0 cm x 0.5 cm absorbable gelatin sponge (AGS), respectively, and thereafter frozen to prepare the biomaterial of rhBMP-2/CPC and rhBMP-2/AGS. Forty-five 24-week-old New Zealand rabbits (weight 2.5-3.5 kg) were randomly divided into 3 groups: group A (n=17), group B (n=11) and group C (n=17). With the exposure and removal of L5,6 transverse process's posterior bone cortex in all the rabbits, the corresponding cancellous bones were exposed and the posterior bilateral intertransverse bone grafting of L5,6 were performed on the three groups, then the rhBMP-2/CPC, rhBMP-2/AGS and CPC was implanted into the rabbits of group A, B and C, respectively. Gross observation, histology assay and image examination were conducted 4, 8 and 24 weeks after operation.
  
  
  RESULTS
  Decalcified hard tissue section demonstrated obvious callus connections in group A, small pieces of callus in group B, and fibrous connection and few cartilage in group C at 4 and 8 weeks after operation. By Kacena measurement standard, the score of group A, B and C at 4 weeks after operation was (7.30 +/- 0.76), (3.68 +/- 1.60) and (1.75 +/- 0.54) points, respectively, and their score at 8 weeks after operation were (8.32 +/- 1.11), (3.75 +/- 1.23) and (1.47 +/- 0.23) points, respectively, indicating there were significant differences between group A and group B as well as between group A and group C at different time points (P < 0.05). Undecalcified hard tissue section demonstrated that there was cancellous bone-like tissue regeneration in group A, and fiber connection around the implants and little ossification in group C at 4 and 8 weeks after operation. By three dimensions reconstructed CT, group A, B and C scored (2.50 +/- 0.57), (1.00 +/- 0.00) and (1.00 +/- 0.00) points respectively, indicating there was a significant difference between group C and groups A and B as well as between group A and group B (P < 0.05).
  
  
  CONCLUSIONS
  As a carrier of rhBMP-2, the CPC is capable of promoting spine bone fusion in rabbits and is a new type of artificial bone repair material.
authors.affiliation: Department of Orthopaedics, Zhongshan Hospital, Fudan University, Shanghai, 200032, P.R. China.
authors.forename: Rongzhou
authors.initials: R
authors.lastname: Zhong
authors.forename: Qinming
authors.initials: Q
authors.lastname: Fei
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Tongyi
authors.initials: T
authors.lastname: Chen
authors.forename: Changsheng
authors.initials: C
authors.lastname: Liu
authors.forename: Zuolin
authors.initials: Z
authors.lastname: Long
authors.forename: Ruichuan
authors.initials: R
authors.lastname: Yu
authors.forename: Heqing
authors.initials: H
authors.lastname: Huang
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D004337:Drug Carriers; D005260:Female; D008297:Male; D008422:Materials Testing; D010012:Osteogenesis; D011817:Rabbits; D011994:Recombinant Proteins; D013123:Spinal Fusion / Q000379:methods*; D016212:Transforming Growth Factor beta
chemical_list: D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D004337:Drug Carriers; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2