[Morphological and biomechanical study on in vivo osteogenesis after repair of cranial defects with plastic engineered bone in rabbits].
OBJECTIVE
To investigate the morphology and biomechanics of in vivo osteogenesis after repairing rabbit skull defects with plastic engineered bone which was prefabricated with alginate gel, osteoblasts and bone granules.


METHODS
Twenty-eight rabbits were divided into group A (n=16), group B (n=8) and group C (n=4). The bilateral skull defects of 1 cm in diameter were made. Left skull defects filled with alginate gel-osteoblasts-bone granules (group A1) and right skull defects filled with alginate gel-bone granules (group A2). The defects of group B was left, as blank control and group C had no defect as normal control. The morphological change and bone formation were observed by methods of gross, histology and biomechanics.


RESULTS
In group A1, the skull defects were almost entirely repaired by hard tissue 12 weeks after operation. The alginate gel-osteoblasts-bone granule material had changed into bone tissue with few bone granules and some residuary alginate gel. The percentage of bone formation area was 40.92% +/- 19.36%. The maximum compression loading on repairing tissue of defects was 37.33 +/- 2.95 N/mm; the maximum strain was 1.05 +/- 0.20 mm; and loading/strain ratio was 35.82 +/- 6.48 N/mm. In group A2, the alginate and bone granules material partially changed into bone tissue 12 weeks after operation. The percentage of bone formation area was 18.51% +/- 6.01%. The maximum compression loading was 30.59 +/- 4.65 N; the maximum strain was 1.35 +/- 0.44 mm; and the loading/strain ratio was 24.95 +/- 12.40 N/mm. In group B, the skull defects were mainly repaired by membrane-like soft tissue with only few bone in marginal area; the percentage of bone formation area was 12.72% +/- 9.46%. The maximum compression loading was 29.5 +/- 2.05 N; the maximum strain was 1.57 +/- 0.31 mm; and the loading/strain ratio was 19.90 +/- 5.47 N/mm. In group C, the maximum compression loading was 41.55 +/- 2.52 N; the maximum strain was 0.95 +/- 0.17 mm; and the loading/strain ratio was 47.57 +/- 11.22 N/mm.


CONCLUSIONS
The plastic engineered bone prefabricated with alginate gel-osteoblasts-bone granule may shape according to the bone defects and has good ability to form bone tissue, whose maximum compression loading can reach 89% of normal skull and the hardness at 12 weeks after operation is similar to that of normal skull.
Liao
Wenbo
W
Division of Stem Cell and Tissue Engineering, State Key Laboratory of Biotherapy , West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P. R. China.
Yang
Zhiming
Z
Deng
Li
L
Li
Xiuqun
X
Sun
Tiancheng
T
Luo
Jingcong
J
Qin
Tingwu
T
Xie
Huiqi
H
D000464:Alginates; D000818:Animals; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D001861:Bone Regeneration; D018786:Bone Substitutes; D016025:Bone Transplantation / Q000379:methods*; D005260:Female; D005782:Gels; D020723:Glucuronic Acid; D048091:Guided Tissue Regeneration; D006603:Hexuronic Acids; D008297:Male; D010006:Osteoblasts; D011817:Rabbits; D011897:Random Allocation; D012886:Skull / Q000293:injuries* / Q000503:physiopathology / Q000601:surgery*; D023822:Tissue Engineering
D000464:Alginates; D001672:Biocompatible Materials; D018786:Bone Substitutes; D005782:Gels; D006603:Hexuronic Acids; D020723:Glucuronic Acid