文档介绍：Definition
Osteoarthritis is a disease of complex etiology that results in loss of normal function due to breakdown of d psychological impact of this devastating disease.
II. Pathogenesis
Osteoarthritis is primarily a disease of the articular cartilage. However, subchondral bone, synovium, ligament and supporting neuromuscular apparatus, if damaged will contribute to accelerated cartilage degradation. The components of articular cartilage include type II and other collagens, proteoglycans and chondrocytes. Nutrition of chondrocytes is provided by diffusion from the blood supply of subchondral bone and synovial fluid.
NORMAL
OSTEOARTHRITIS
capsule
synoviurn —1
bone
altered contour of bone
synovial hypertrophy
thickened capsule cyst formation and scl&rosis in subchondral bone shelving 'fibnllated' cartilage ost^ophytic lipping
cartilage —I
Figure 1- Diagram of a joint, normal on the left and osteoarthritic on the right
Types III, IV, IX, X and XI collagen make up 10-20% of the total cartilage collagen and maintain the stability of Type II collagen. For example, type IX and XI collagen regulate its fibril diameter. The proteoglycan aggrecan is highly hydrophilic, with low viscosity. Its ability to retain water under conditions of load and release it during unloading imparts to articular cartilage its elastic property, allowing the cartilage to function as a shock absorber in the diarthrodial joint. An abnormality in the structure of these proteins leads to cartilage with poor function and thus to the development of osteoarthritis.
Biochemistry of Articular Cartilage
^Glycosamtnoglycan subunits + Procollagen*- Chondrocyte --*< Hyaluronic acid Link pfotein
Type 11 caUagen ProcsXycan
hh ■ ■. 、 aggregates
• Forma struciural matrix
Provide *compre&sabie- struclurfi
InhlbM calcl^c^Uon
Figure 2- The Biochemistry of Articular cartilage
Figure 3- Diagram of Articular Cartilage structure
Interleukin 1 (IL-1), a cytokine produced by mononuclear ce