ABSTRACT
BACKGROUND:Bone marrow mesenchymal stem cel s and al ogenic bones are commonly used as seed cel s and scaffolds, respectively, for constructing tissue-engineered cartilage through in vitro co-culture. The loose body of the knee joint can survive in the articular cavity for a long time, and maintain certain characteristics of cartilage tissues. Therefore, the articular cavity can provide a good environment for the growth and development of chondrocytes. OBJECTIVE:To investigate the effect of bone marrow mesenchymal stem cel s co-cultured with al ogenic bone in the articular cavity. METHODS:Bone marrow mesenchymal stem cel s were isolated from five newborn New Zealand white rabbits. One adult New Zealand rabbit was enrol ed to prepare al ogenic bone for co-culture with bone marrow mesenchymal stem cel s. Afterwards, bone marrow mesenchymal stem cel s and al ogenic bone composites were cultured in the articular cavity (intracavitary culture group) or in vitro as in vitro culture group, respectively;the normal cartilage tissues grew in the articular cavity as control group. Cel s were observed by hematoxylin-eosin staining and type II col agen immunohistochemistry staining at 4, 8 and12 weeks of culture. RESULTS AND CONCLUSION:At 12 weeks culture, hematoxylin-eosin staining showed:in the control group, chondrocytes arranged tightly and directional y with red stained cytoplasm and cartilage matrix as wel as blue nuclei;in the intracavitary culture group, the scaffold was mostly absorbed and chondrocytes grew into the scaffold in a certain direction with smaller shape, while cytoplasm and cartilage ma trix were red stained, blue nuclei appeared;in the in vitro culture group, abundant chondrocytes proliferated in a disordered arrangement. Immunohistochemistry staining showed:the absorbance ( A) values in the intracavitary culture group showed a continuous increase, but no obvious change was in the other two groups. Moreover, at 4, 8 and 12 weeks of culture, A values in the control group and intracavitary culture group were significantly higher than that in the in vitro culture group (P0.05). These results suggest that the tissue-engineered cartilage can be constructed by bone marrow mesenchymal stem cells co-cultured with allogenic bone under in vitro and in vivo environment, especially in the articular cavity.