Expression Of Cathepsin-k In Cartilage Of Osteoarthritis

Objective to observe the distribution and expression of Cathepsin-k in human normal articular cartilage and osteoarthritic articular cartilage and to explore the relation between the Cathepsin-k expression and the pathogenesis of osteoarthritis.Methods to collect human normal articular cartilage and osteoarthritic articular cartilage in the knee joints and RT-PCR was used to measure mRNA levels of cathepsin K in total RNA extracted from normal cartilage and osteoarthritic cartilage in the knee joints. Immunohistochemistry was used to study the distribution and expression of Cathepsin-k in normal cartilage and osteoarthritic cartilage in the knee joints.Results Increased expression of Cathepsin-k was found near sites of matrix destruction in articular chondrocytes, particularly in clusters of proliferating cells, At the onset of cartilage degeneration, Obvious increased expression of cathepsin K was found in the vicinity of articular cartilage defects in early osteoarthritic lesions (the surface layer of articular cartilage and the vicinity of clusters of proliferating cells), Cathepsin-k was only seen in a small number of chondrocytes in normal cartilage. The expression of Cathepsin-k in osteoarthritis were obviously higher than those in normal cartilage (P<0.05)and the expression of Cathepsin-k in advanced group were obviously higher than those in mild group at the mRNA level(P<0.05).Conclusion the up regulation and temporospatial distribution of Cathepsin-k in osteoarthritis cartilage suggests a role for this enzyme in the pathogenesis of osteoarthritis,especially at the onset, Cathepsin-k is closely involved in cartilage degenevation is primarily from the increase of Cathepsin-k. These data may provide new clues for the development of treatments aimed at preventing cartilage degeneration.