Proteoglycan and collagen synthesis of cultured fibrochondrocytes from the human knee joint meniscus

Fibrochondrocytes isolated from different parts of the human knee joint meniscus were cultured, and their morphology and ability to synthesize matrix components were investigated. The mid-portion of the medial meniscus was divided into two parts (the outer one-third and the inner two-thirds), and cells were obtained for culture by pronase and collagenase digestion. The appearance of the fibrochondrocytes was different in monolayer culture from that of both articular chondrocytes and fibroblasts. However, there was no difference between the cells obtained from the two different parts of the meniscus. Although proteoglycan synthesis by cells from the inner two-thirds was higher than that by cells from the outer one-third of the meniscus, there was no difference in the collagen synthesis. Fibrochondrocytes from the meniscus were found to synthesize cartilage-like proteoglycan. Proteoglycan synthesis by meniscus cells and articular chondrocytes was stimulated by TGF-beta 1 in a dosage-dependent manner. These findings indicated that fibrochondrocytes possessed similar characteristics to articular chondrocytes in terms of proteoglycan metabolism.