ABSTRACT
BACKGROUND:Loose bodies in the knee are found to survive for a long term and maintain certain histophysiological properties of cartilage tissue. Therefore, a bold hypothesis is proposed that the joint cavity may be a preferred environment for chondrocyte growth and development, supporting the concept of “intracavitary culture and intracavitary transplantation”. OBJECTIVE:To observe the trait difference of chondrogenic culture with alogenic decalcified bone matrix and bone marrow mesenchymal stem cels in the joint cavity orin vitro versus cartilage in the same cavity. METHODS:There were three groups in this experiment: inin vitro culture group, bone marrow mesenchymal stem cels from newborn rabbits undergoing chondrogenic culture were co-cultured with decalcified bone matrix from adult rabbitsin vitro; in intracavitary culture group, bone marrow mesenchymal stem cels from newborn rabbits undergoing chondrogenic culture were co-cultured with decalcified bone matrix from adult rabbits in the joint cavity; normal cartilage in the same cavity served as control group. RESULTS AND CONCLUSION: (1) After 12 weeks of culture, in the in vitro culture group, hematoxylin-eosin staining showed a smal amount of chondrocytes proliferated, with blue-stained nuclei; toluidine blue staining showed chondrocytes arranged disorderly, surrounded by a smal amount of matrix; Masson staining showed a smal positive area and irregular cellarrangement; type II colagen immunohistochemistry staining showed a few of yelow particles in the cytoplasm and extracelular matrix. (2) After 12 weeks of culture, in the intracavitary culture group, hematoxylin-eosin staining showed proliferation of chondrocytes with blue-stained nuclei; toluidine blue staining showed cluster-shaped arrangement of chondrocytes surrounded by the matrix with lacuna formation; Masson staining showed there were many positive cels with blue-stained matrix that arranged in a certain stress direction; immunohistochemical identification of type II colagen was positive, and brown-yelow stained particles could be discerned in the extracelular matrix. These findings indicate that tissue-engineered cartilage can be generated by co-culture of alogenic decalcified bone matrix and bone marrow mesenchymal stem cels in the joint cavity orin vitro, and the cartilage cultured in the joint cavity is more close to normal cartilage than that cultured in vitro.