The Regeneration Of Tissue Engineered TMJ Condyle:A Primary Study

ObjectIn this study,we investigated the feasibility of regenerating specific three-dimensional osteochrondral composition in different microspheres of different animals after we successfully fabricated cartilage tissue by different ways in vitro,which was used to be sutured with bone phase cell-scaffold complex.MethodsFirstly,fabricate cartilage tissue and bone phase cell-scaffold composition in vitro.Two techniques were employed to fabricate cartilage respectively.Method one: PGA/PLA scaffolds were seeded with high-density chondrocytes.And then they were incubated to inducing cartilage formation.Method two: construction of chondrocyte cell sheet in vitro.Bone phase cell-scaffold complex was fabricated by seeding BMSCs on PCL/HA scaffolds and induce them osteogenesis.Histological,immunohistochemical staining and biochemical analysis were employed to evaluate the capacity of chondrogenesis and osteogenesis.Secondly,two kinds of cartilage tissue were respectively sutured with bone phase cell-scaffold complex(biphasic scaffold group and cell sheet group).They were separately implanted into nude mice,subcutaneous,intramuscular of minipig to regenerate biological condyle.Histological structure was evaluated.Lastly,the above two methods were used to regenerate biological condyle in the goat condyle in situ.And the results were evaluated.ResultsIn vitro two methods can be successfully constructed cartilage tissue with cartilage specific histological characteristics and a certain mechanical properties.As to the constructed bone phase cell-scaffold complex in vitro,BMSCs adhered well on the scaffold and displayed good osteogenic potential.Both biphasic scaffold group and cell sheet group could regenerated biological condyle with osteochondral structure in nude mice.The regenerated cartilage layer was continuous,homogeneous,single,bloodless healthy cartilage.A large nμmber of chondrocytes were juxtaposed in the typical cartilage lacunae single or in two.Cartilage lacunae was surrounded by extracellular matrix like glycosaminoglycan and collagen fibers.The upper cartilage was closely connected to the subchondral tissue without gap.New bone could be detected in the clearance of bone phase scaffold.There were no differences between the two groups.In the large animal subcutaneous,intramuscular and in situ,biphasic scaffold group could not regenerate biological condyle because of inflammation reaction caused by PGA/PLA residues.However,cell sheet group could regenerate biological condyle with primary osteochondral structure.The regenerated condyle boned firmly with native bone.TMJ capsule superior cavity was existence with no ankylosis occurred,maximμm mouth opening of 4 fingers.But the regenerated cartilage layer was adhered firmly with TMJ disc.Conclusion1.Both two methods successfully construct cartilage tissue in vitro.2.Two kinds of cartilage tissue sutured with bone phase cell-scaffold complex could successfully regenerate biological condyle with osteochondral structure in nude mice.3.Biphasic scaffold group could not regenerate biological condyle in large animal model because of the inflammation reaction caused by PGA/PLA residues.Nevertheless,cell sheet group which had no inflammation reaction caused by polymer biomaterials could regenerate biological condyle with primary osteochondral structure in different environment of large animals.