Use of bone morphogenetic protein 2 and diffusion chambers to engineer cartilage tissue for the repair of defects in articular cartilage.
OBJECTIVE
To examine the ability of cartilage-like tissue, generated ectopically in a diffusion chamber using recombinant human bone morphogenetic protein 2 (rHuBMP-2), to repair cartilage defects in rats.


METHODS
Muscle-derived mesenchymal cells were prepared by dissecting thigh muscles of 19-day postcoital rat embryos. Cells were propagated in vitro in monolayer culture for 10 days and packed within diffusion chambers (10(6)/chamber) together with type I collagen (CI) and 0, 1, or 10 microg rHuBMP-2, and implanted into abdominal subfascial pockets of adult rats. Tissue pellets were harvested from the diffusion chambers at 2 days to 6 weeks after implantation, and examined by histology, by reverse transcription-polymerase chain reaction (PCR) for aggrecan, CII, CIX, CX, and CXI, MyoD1, and core binding factor a1/runt-related gene 2, and by real-time PCR for CII. Tissue pellets generated in the chamber 5 weeks after implantation were transplanted into a full-thickness cartilage defect made in the patellar groove of the same strain of adult rat.


RESULTS
In the presence of 10 microg rHuBMP-2, muscle-derived mesenchymal cells expressed CII messenger RNA at 4 days after transplantation, and a mature cartilage mass was formed 5 weeks after transplantation in the diffusion chamber. Cartilage was not formed in the presence of 1 microg rHuBMP-2 or in the absence of rHuBMP-2. Defects receiving cartilage engineered with 10 microg rHuBMP-2 were repaired and restored to normal morphologic condition within 6 months after transplantation.


CONCLUSIONS
This method of tissue engineering for repair of articular defects may preclude the need to harvest cartilage tissue prior to mosaic arthroplasty or autologous chondrocyte implantation. Further studies in large animals will be necessary to validate this technique for application in clinical practice.
Nawata
Masashi
M
Department of Orthopaedic Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan.
Wakitani
Shigeyuki
S
Nakaya
Hiroyuki
H
Tanigami
Akira
A
Seki
Toyokazu
T
Nakamura
Yukio
Y
Saito
Naoto
N
Sano
Kenji
K
Hidaka
Eiko
E
Takaoka
Kunio
K
D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000627:therapeutic use*; D002358:Cartilage, Articular / Q000637:transplantation*; D002454:Cell Differentiation; D019902:Chondrocytes / Q000166:cytology; D015194:Diffusion Chambers, Culture; D004622:Embryo, Mammalian / Q000166:cytology; D006801:Humans; D007592:Joint Diseases / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery*; D007719:Knee Joint; D018482:Muscle, Skeletal / Q000166:cytology / Q000196:embryology; D051381:Rats; D011916:Rats, Inbred F344; D011994:Recombinant Proteins / Q000627:therapeutic use; D013848:Thigh / Q000196:embryology; D023822:Tissue Engineering / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000627:therapeutic use*
C525718:BMP2 protein, human; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2