Cell proliferation in osteoarthritic human cartilage

Objective: Osteoarthritic (OA) cartilage is histologically characterized by the appearance of cell clusters, which are probably generated by mitotic c ell division The aim of this study was to analyze the distribution and amou nt of proliferating chondrocytes in healthy and osteoarthritic cartilage sy stematically. Materials and methods: 6 normal and 43 osteoarthritic cartila ge/bone samples were obtained during autopsies or total knee replacements. The cartilage specimens were stained with safranin-o and scored according t o the Mankin-System. Proliferating chondrocytes were identified by immunohi stochemical detection of the antigen PCNA. The number of proliferating chon drocytes was determined by counting 100 chondrocytes in each cartilage laye r. Results: in normal and osteoarthritic human cartilage, proliferating cho ndrocytes were detected. The amount of proliferating chondrocytes increased during the progression of OA cartilage changes. Expression of PCNA was det ermined in single chondrocytes and clustered chondrocytes. Chondrocyte cell division was activated specifically in cartilage with severe OA changes. C onclusions. Osteoarthritic chondrocytes, which are known to increase the sy nthesis of different matrix proteins, show the phenomenon of mitotic cell d ivision. Whether the increased amount of proliferating chondrocytes fails t o compensate the rate of apoptotic chondrocytes, or whether the generation of cell clusters represents only a fruitless repair effort is a subject of recent research. However, the induction of chondrocyte proliferation is a p otential target in the treatment of OA.