J Korean Assoc Maxillofac Plast Reconstr Surg.  2012 Jan;34(1):1-11.

3-Dimensional Micro-Computed Tomography Study on Bone Regeneration with Silk Fibroin, rh-Bone Morphogenetic Protein Loaded-Silk Fibroin and Tricalcium Phosphate Coated-Silk Fibroin in Rat Calvaria Defect

• Pang EO
• Park YJ
• Park SH
• Kang ES
• Kweon H
• Kim SG
• Ko CY
• Kim HS
• Nam JH
• Ahn JH
• Chun JH
• Lee BM

Abstract

PURPOSE
The purpose of this study was to evaluate the bone regeneration capacity of silk fibroin (SF) when combined with beta tricalcium phosphate (beta-tricalcium phosphate [TCP]) and rh-bone morphogenetic protein (BMP) in vivo by micro-computed tomography (CT), soft x-ray, and histological analysis.
METHODS
A total of 56 critical size defects formed by a trephine bur made on 28 adult female Spague-Dawley rats were used for this study and the defect size was 5.0 mm in diameter. The defects were transplanted with (1) no graft material (raw defect), (2) autogenous bone, (3) SF (10 microg), (4) SF-BMP (10 microg, 0.8 microg each), and (5) SF+beta-TCP (10 microg). At 4 and 8 weeks after operation, the experimental animals were sacrificed. Samples were evaluated with soft x-ray, histological examinations and 3-dimensional micro-CT analysis.
RESULTS
In the 3-dimensional micro-CT evaluation, bone volume and bone surface data were higher in the SF-BMP (12.8+/-1.5, 138.6+/-45.0 each) (P<0.05) and SF-TCP (12.3+/-1.5, 144.9+/-30.9 each) group than in the SF group (6.1+/-3.3, 77.2+/-37.3 each) (P<0.05), except for the autogenous group (15.0+/-3.0, 190.7+/-41.4 each) at 4 weeks. At 8 weeks, SF-BMP (16.8+/-3.5, 173.9+/-34.2 each) still revealed higher (P<0.05) bone volum and surface, but SF-TCP (11.3+/-1.5, 1132.9+/-52.1 each) (P=0.5, P=0.2) revealed the same or lower amount compared with the SF group (13.8+/-2.7, 127.5+/-44.8 each). The % of bone area determined by radiodensity was higher in the SF-TCP (31.4+/-9.1%) and SF-BMP (36.2+/-16.2%) groups than in the SF (19.0+/-10.4) group at the period of 4 weeks. Also, in the histological evaluation, the SF-BMP group revealed lower inflammation reaction, lower foreign body reaction and higher bone healing than the SF group at postoperative 4 weeks and 8 weeks. The SF-TCP group revealed lower inflammation at 4 weeks, but accordingly, as the TCP membrane was absorbed, inflammatory and foreign body reaction are increased at 8 weeks.
CONCLUSION
The current study provides evidence that the silk fibrin can be used as an effective grafted material for tissue engineering bone generation through a combination of growth factor or surface treatment.

Keyword

Silk fibroin; Rat calvarial defect; Bone regeneration; Micro-CT

MeSH Terms

Adult
Animals
Bone Regeneration
Calcium Phosphates
Female
Fibrin
Fibroins
Foreign-Body Reaction
Humans
Inflammation
Membranes
Rats
Silk
Skull
Tissue Engineering
Transplants
Calcium Phosphates
Fibrin
Fibroins
Silk