ABSTRACT
BACKGROUND: Preparing a scaffold with cartilage derived components and good initial mechanical strength is the direction of tissue engineering cartilage research. OBJECTIVE: To prepare porous acellular osteochondral scaffolds, and to explore their mechanical properties and cell compatibility. METHODS: Osteochondral bone from the porcine knee joint was taken, and then porous osteochondral scaffolds were made by laser microporation technology. Subsequently, the scaffolds were decellularized chemical methods. Scaffold structure was observed by scanning electron microscopy, and the compression modulus of the scaffolds was determined. Bone marrow mesenchymal stem cells were cultured in L-DMEM containing 10% fetal bovine serum (control group) and cultured in the medium extract of porous acellular osteochondral scaffolds (experimental group), respectively. Cell proliferation was detected by cell counting kit-8 method within 5 days of culture. Bone marrow mesenchymal stem cells were seeded on the porous acellular osteochondral scaffolds, and within 28 days of co-culture, cell growth was observed by hematoxylin-eosin staining and toluidine blue staining. RESULTS AND CONCLUSION: (1) Observation under scanning electron microscopy: The porous acellular osteochondral scaffolds had the smooth surface with evenly distributed pores. The pores of the scaffold extended longitudinally into the subchondral bone. (2) Mechanical properties: The average compressive modulus of porous acellular osteochondral scaffolds was 0.77 MPa, which was close to the compression modulus of the normal cartilage (1.15 MPa). (3) Cell counting kit-8 test: There were no differences in cell proliferation between the control and experimental groups at 1, 2, 3, 4 and 5 days of culture. (4) Cell-scaffold co-culture: A large amount of bone marrow mesenchymal stem cells were observed to be adherent to the scaffold after 1 day of culture through hematoxylin-eosin and toluidine blue staining. However, as time went on, a few cells adhered to the pore wall or grew into the pores at 7 and 21 days of culture. There were also some adherent cells but a large amount of cell masses formed in the pores at 28 days of culture. To conclude, the porous acellular osteochondral scaffold has good mechanical properties and cell compatibility.
ABSTRACT
BACKGROUND: The application of mesenchymal stem cells (MSCs) in the treatment of cartilage damage has become a hot spot of research. Further studies on the distribution of MSCs in the body after injection and on the underlying mechanism of action are needed. OBJECTIVE: To observe the migration of bone marrow mesenchymal stem cells (BMSCs) after injection into the region of osteochondral defect. METHODS: Thirty Sprague-Dawley rats were randomized into two groups (n=15 per group). In the control group, the femoral tochlear was exposed but an osteochondral defect was not made; and after the suture, PKH26-labeled BMSCs were directly injected into the articular cavity of rats. In the experimental group, a cartilage defect of 1 mm in diameter and 1 mm in depth was made in the rat femoral trochlea, and 5×106PKH26-labeled BMSCs were injected into the defect after operation. At 1, 3 and 7 days after injection, the femoral condyle was taken to make frozen sections followed by DAPI staining. The distribution of BMSCs was observed under laser scanning confocal microscope. RESULTS AND CONCLUSION: In the control group, PKH26-labeled BMSCs were not transferred to the subchondral bone. In the experimental group, BMSCs were detected in the subchondral bone area at 1, 3 days after injection of PKH26-BMSCs in the bone cartilage defect area, and the BMSCs were also found in the bone marrow cavity at 7 days after injection. In conclusion, BMSCs in the articular cavity cannot migrate into the subchondral bone and bone marrow cavity unless the cartilage of the femoral condyle is damaged.