OBJECTIVETo investigate the expressive changes of collagen I, II and aggrecan during the aging of the human costal chondrocytes cultured in vitro, in order to select the best chondrocytes for cartilage engineering.

METHODSThe human costal chondrocytes from the different passages (P1-P5) were harvested. The morphological changes and cell proliferation rate were observed, and the quantity of glycosaminoglycans (GAGs) was examined in each passage with alcian blue precipitation. The expression of collagen I, II and aggrecan was measured with immunohistochemistry and RT-PCR method.

RESULTSFrom the third passage, the human costal chondrocytes were transformed into fibroblast-like cell morphology; and the GAGs content in each passage was decreased and became significantly low in the third passage. The expression of the collagen I, II was consistent in the protein level with that in the mRNA level. Before the second passage, the expression of collagen II was high while the collagen I was low. After the second passage, the expression of collagen II decreased while the collagen I increased. The expression of aggrecan was high before the third passage, and then became low in the fourth passage.

CONCLUSIONWith the examinations of the cell proliferating rate and cell functions in human chondrocytes cultured in vitro, the chondrocytes of the second passage seem suitable for human cartilage engineering.