In vitro response of articular cartilage from mature mice to human transforming growth factor beta.

The ability of human transforming growth factor-beta 1 (hTGF-beta 1) to induce proliferation and matrix synthesis in articular cartilage of aging mice was studied using an organ culture system of mandibular condylar cartilage. An increased incorporation of 3H-thymidine into DNA and of 35S-SO4 into sulfated glycosaminoglycans was observed in cultures supplemented with 1-10 ng/ml TGF-beta and with 1% fetal calf serum. In these cultures numerous clusters of chondrocytes containing a well-developed rough endoplasmic reticulum were seen. Articular cartilage from mature animals often develops osteoarthritic degenerative lesions, thus the induction of cell proliferation and of matrix synthesis may be an indication of a tissue repair process in cartilage from maturing animals.