OBJECTIVETo obtain large amount of differentiated chondrocytes in vitro, examine and compare the biological characterization of rabbits' articular chondrocyte cultured in different density in vitvo.

METHODSFrom November 2001 to June 2004, articulate tissues were obtained from the joints of the adult rabbits. Chondrocytes were isolated from the cartilage tissue with type II collagenase digestion and cultured in DMEM/F-12 supplemented with 20% fetal bovine serum (FBS). The chondrocytes were cultured with low density of monolayer culture and high density of confluent culture respectively. The differentiated phenotype was evaluated by histochemistry or immunohistochemistry.

RESULTSWhen chondrocytes cultured in monolayer and in low density, it proliferated rapidly during the three generations, but with the same time, dedifferentiation was also rapid. After the third passage, most of the passage cells lost the phenotype, and the proliferation also stagnated. While chondrocytes cultured in high density, dedifferentiation slowed down. And even the phenotypes of the dedifferentiated chondrocyte which were cultured in low density could reduced partly by followed high density culture.

CONCLUSIONSCulture chondrocytes by high density in vitro can effectively maintain the differentiated phenotype of chondrocyte. It also keeps the proliferation character as monolayer culture. The dedifferentiated chondrocyte caused by many passages could redifferentiate partly. So it is indicated that confluent culture of original or expanded chondrocytes in high density is a better culture methods than culture in low density.