Arthroscopic, histological and MRI analyses of cartilage repair after a minimally invasive method of transplantation of allogeneic synovial mesenchymal stromal cells into cartilage defects in pigs.
OBJECTIVE
Transplantation of synovial mesenchymal stromal cells (MSCs) may induce repair of cartilage defects. We transplanted synovial MSCs into cartilage defects using a simple method and investigated its usefulness and repair process in a pig model.


METHODS
The chondrogenic potential of the porcine MSCs was compared in vitro. Cartilage defects were created in both knees of seven pigs, and divided into MSCs treated and non-treated control knees. Synovial MSCs were injected into the defect, and the knee was kept immobilized for 10 min before wound closure. To visualize the actual delivery and adhesion of the cells, fluorescence-labeled synovial MSCs from transgenic green fluorescent protein (GFP) pig were injected into the defect in a subgroup of two pigs. In these two animals, the wounds were closed before MSCs were injected and observed for 10 min under arthroscopic control. The defects were analyzed sequentially arthroscopically, histologically and by magnetic resonance imaging (MRI) for 3 months.


RESULTS
Synovial MSCs had a higher chondrogenic potential in vitro than the other MSCs examined. Arthroscopic observations showed adhesion of synovial MSCs and membrane formation on the cartilage defects before cartilage repair. Quantification analyses for arthroscopy, histology and MRI revealed a better outcome in the MSC-treated knees than in the non-treated control knees.


CONCLUSIONS
Leaving a synovial MSC suspension in cartilage defects for 10 min made it possible for cells to adhere in the defect in a porcine cartilage defect model. The cartilage defect was first covered with membrane, then the cartilage matrix emerged after transplantation of synovial MSCs.
Section of Orthopedic Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Tomomasa
T
Nakamura
Ichiro
I
Sekiya
Takeshi
T
Muneta
Daisuke
D
Hatsushika
Masafumi
M
Horie
Kunikazu
K
Tsuji
Tatsuo
T
Kawarasaki
Atsuya
A
Watanabe
Shuji
S
Hishikawa
Yasuhiro
Y
Fujimoto
Hozumi
H
Tanaka
Eiji
E
Kobayashi
D000818:Animals; D002357:Cartilage Diseases / Q000473:pathology / Q000628:therapy; D002448:Cell Adhesion; D002454:Cell Differentiation; D049109:Cell Proliferation; D017690:Cell Transplantation / Q000379:methods*; D020219:Chondrogenesis; D005260:Female; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007718:Knee Injuries / Q000473:pathology / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D023421:Models, Animal; D013552:Swine; D013583:Synovial Membrane / Q000166:cytology* / Q000378:metabolism; D013997:Time Factors; D014184:Transplantation, Homologous / Q000379:methods
D049452:Green Fluorescent Proteins