RESUMO
BACKGROUND: To mimic physiological and functional requirements of cartilage and subcondral bone, some recent studies have fabricated bilayered scaffolds for osteochondral tissue engineering in cartilage repair. However, in cartilage repair, and little is reported on the use of a single biomaterial instead of composite biomaterials to fabricate bilayered porous scaffolds. OBJECTIVE: To investigate the biocompatibility of an integrated bilayered porous scaffold fabricated with poly(lactic-co-glycolide) (PLGA), and then to discuss its feasibility of constructing tissue-engineered osteochondral graft. METHODS: The integrated bilayered porous scaffolds were fabricated with PLGA by changing the ultrastructure of scaffold.In vitro,bone marrow mesenchymal stem cells(BMSCs)isolated from rabbits were seeded into the bilayered porous PLGA scaffold, co-cultured for 1 week and then observed under scanning electron microscope. After co-culturing 48 hours,the cells were stained by LIVE/DEAD Kit.In vivo,the composite of DiI-labeled BMSCs and the scaffold or the scaffold alone were implanted subcutaneously into the skin of nude mice, and the implants were taken out and stained by hematoxylin-eosin and DAPI staining at 4 and 8 weeks after implantation. RESULTS AND CONCLUSION: (1) We successfully obtained the bilayered porous scaffolds with different pore sizes (the upper layer:100-200 μm and the lower layer:300-450 μm)and 85% porosity.(2)In the in vitro experiment,the LIVE/DEAD staining showed that BMSCs survived well in the scaffold, and the cells adhered well to the wall of pores in all the scaffolds and extracellular matrix deposition was found under the scanning electron microscope.(3)In the in vivo experiment, shown by the hematoxylin-eosin staining, a small amount of chondrocytes formed in the fibrous tissue in the upper layer and a large amount of trabecular bones in the lower layer were found at 8 weeks after implantation in the experimental group. The close integration between the upper layer and the lower layer appeared. BMSCs could survive for 8 weeks in vivo shown by the DAPI staining.However,in the control group,a little fibrous tissue was found without chondrocytes and apparent trabecular bone, and the scaffold was partially degraded. To conclude, the integrated bilayered porous scaffold fabricated with PLGA alone has good biocompatibility, which is feasibly used in osteochondral tissue engineering.