| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1990: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1989: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1988: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
Expression of differentiated phenotype of articular cartilages is strictly related to the function of joints. Alteration of the phenotype leads to destruction of the cartilage and articular function. Proteoglycan (PG) which is one of the major cartilage-matrix components as well as Type II and other minor collagen show fine alteration in quality and quantity dependently on environment surrounding chondrocytes. The alteration act as signals to chondrocytes and determine functions of them. Therefore, cellular environment would be estimated by examining expression of the differentiated phenotype of chondrocytes and by analyzing cartilage matrix. We studied expression of the differentiated phenotype of chondrocytes in cartilage tissues of disordered human joints, experimental arthritic models (adjuvant induced arthritis of rats and osteoarthritis experimentally induced in rabbit knees) and cultured chondrocytes, particularly based on behaviors of PGs.
We analysed cartilaginous tissues obtai
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ned in total hip replacement from patients with osteoarthritis, rheumatoid arthritis, psoriatic arthritis, or aseptic necrosis of the femoral head. Tissues were also obtained at intervals from experimentally induced adjuvant arthritis in rats and osteoarthritis in rabbit knees. Cultured costal chondrocytes from young rabbits and the cell line (HCS2/8) which was isolated and established from human well differentiated chondrosacoma were used for analysis. For histological examination, paraffin sections (4 mu m thick) of the obtained cartilage tissues were stained with hematoxylin-eosine, saffranin 0, or toluidine blue. For biochemical analysis, they were sliced to pieces after measurement of their wet weight and pulse labeled with H_2^<35>SO_4in Gey-Hanks (9/1) solution for 3 hours. PG was extracted with 4M-GuHCl solution containingprotease inhibitors, fractionated in glycerol density gradient (5-25%) and then precipitated with cetylpyridinium chloride. Molecular sizes of PG and GAG were determined on the basis of ^<35>S content in the precipitates. Cultured cells were analyzed for PGs and GAGs in the same way after addition of sera and extracts from synovial tissue of patients.
Different types pf PGs are found in normal human articular cartilage, rabbit costal cartilaginous tissue, and rabbit cultured costal chondrocytes. PG of larger molecular size is used as an indicator of expression of the differentiated phenotype. In osteoarthritis of the hip, particularly in dislocated osteoarthritis of the hip, sufficient depression was found at the femoral head but cartilage specific PG was eliminated at the primary acetabulum because of little involvement in joint functions. In the secondary acetabulum, cartilaginous differentiation was suggested in undifferentiated mesenchymal cells. In cases of rheumatoid arthritis and psoriasis, remarkable changes were found in cellular functions even at a stage of mild damage in the joint cartilage and particular aspect was observed in joint chondrocytes of patients with systemic disease. In adjuvant arthritis, expression of the differentiated phenotype be markedly affected prior to histological changes in synovium and cartilaginous tissues, and might closely related to the cell function. In the experimental model of osteoarthritis induced in rabbit knees, PG molecular size showed a distinctive trend to recover although it remarkably varied at a time, and impressed differences in cellular reaction between traumatic and immunological disorders. Less
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