Degenerative Changes In Articular Cartilage Research Articles

Collagen IX

Collagen IX was identified as a distinct component of cartilage about 10 years ago. Composed of three polypeptide chains, its heterotrimeric molecules are located on the surface of type II collagen fibrils in cartilage. The interaction between collagens II and IX is stabilized by covalent crosslinks. The location of collagen IX molecules on fibril surfaces suggests that they represent macromolecular bridges between fibrils and other matrix components in cartilage, and that collagen IX is important for the cohesive and compressive properties of cartilage. Transgenic mice with mutations in a type IX gene develop normally, but show degenerative changes in articular cartilage after birth. Additional evidence for the importance of collagen IX in human articular cartilage comes from the recent finding that a mutation in one of the collagen IX genes causes multiple epiphyseal dysplasia. The mild complaints in affected individuals with the mutation suggest that mutations in type IX collagen genes may represent genetic risk factors for late onset osteoarthritis.

Articular Cartilage Surface Changes Following Immobilization of the Rat Knee Joint

Normal articular cartilage surfaces are not flat and smooth, but are contoured with various degrees of roughness. We applied the articular surface classification system developed by Jurvelin to evaluate contour and surface quality changes in rat patellae after varying periods of knee joint immobilization. In our study, one knee joint was immobilized in each of 20 rats, while the contralateral joint served as a free-moving control. Scanning electron-microscopic montages were constructed and the entire cartilage surface was subdivided by contour and surface quality areas. The total articular surface area and all contour and surface quality subclass areas were then calculated for both joints in each rat. Numerous studies have demonstrated that joint immobilization induces degenerative changes in articular cartilage. We found a correlation between the duration of immobilization and changes in the measured area of contour and surface quality subclasses. There was a statistically significant decrease of the even surface area in the weight-bearing, central region of the patellae. This corresponded to a statistically significant increase in the slightly uneven articular surface area usually found just peripheral to this weight-bearing region. There was also a less pronounced (but not statistically significant) decrease in the smooth surface area with a corresponding increase in the rough surface area of the patellae following immobilization. Closer examination of these surfaces revealed that the superficial cartilage layer in the central, weight-bearing areas had less ground substance than other areas. In addition, there appeared to be two different fiber diameters in the superficial cartilage layer of the rat patellae. These were predominantly collagen fibers (142.3 +/- 31.5 nm in diameter) generally running parallel to the long axis of the patella, occasionally random in orientation, and sometimes presenting on the cartilage surface as collagen tips and much more scarce fibrils (20.0 +/- 4.8 nm in diameter) randomly crossing the larger collagen fibers.

Evaluation of intra-articularly administered sodium monoiodoacetate-induced chemical injury to articular cartilage of horses

Summary Three doses of sodium monoiodoacetate (mia) were used to induce degenerative changes in articular cartilage in middle carpal joints of horses. Twelve young (2- to 5-year-old) horses, free of lameness, were randomly allotted to 3 groups. One middle carpal joint of each horse was injected with 0.9% NaCl solution (control joint). The contralateral middle carpal joint was injected with 0.09 mg of MlA/kg of body weight (group 1); 0.12 mg/kg (group 2); or 0.16 mg/kg (group 3). After mia administration, horses were allowed ad libitum exercise in a 2-acre paddock for 12 weeks. At the end of the study, gross and microscopic tissue changes were evaluated and biochemical analyses of articular cartilage were done. Grossly, diffuse partial thickness articular cartilage lesions were observed in group-2 (n = 2) and group-3 (n = 4) horses, but not in group-1 horses. Articular cartilage uronic acid content was significantly (P < 0.03) decreased in all mia-injected joints, compared with controls. Articular cartilage matrix staining with safranin-O was decreased in 3 of 4 mia- injected joints of group-1 horses and in all mia-injected joints of group-2 and group-3 horses, compared with controls (P < 0.06). Microscopic degenerative changes in articular cartilage were not significantly different between mia-injected and control joints in group-1 horses, but were increased (P<0.06) in all MlA-injected joints of group-2 and group-3 horses, compared with controls. Qualitatively, decreased matrix staining and degenerative changes were more severe in group-3 horses. On the basis of articular cartilage gross and microscopic changes, as well as biochemical changes, 0.12 mg of mia/kg injected intra-articularly was determined to induce moderate degrees of articular cartilage degeneration. This model of chemically induced articular cartilage injury could be useful for evaluating treatment effects of anti-arthritic drugs in horses.

甲状腺機能低下を伴った成人の大腿骨近位骨端離開の１例

Clinical history from the onset to one year and two months after operation of slipped capital femoral epiphysis in an adult male patient aged 27 years was reported.The slipping of the femoral head occurred suddenly one week after the onset of pain in the left hip which was operated on by multiple pinning. While the clinical course was favourable, degenerative changes developed in the femoral head approximately one year after operation.Hypothyroidism was revealed by the hemanalysis and Tc scan, and the biopsy of the coexistent arthropathy of the elbow joint demonstrated the villous hypertrophy of synovial membrane and the degenerative changes in articular cartilage.

The effect of partial rostral hemimandibulectomy on mandibular mobility and temporomandibular joint morphology in the dog.

Partial rostral hemimandibulectomy was performed in 10 adult dogs. The temporomandibular joints (TMJs) were examined radiographically and tomographically before surgery, and mandibular stability was evaluated before and immediately after surgery. Radiographic, tomographic, and hemimandibular mobility assessments were made again at months 3 and 6. The TMJs were examined grossly and histologically in five dogs euthanatized at month 3 and in five dogs euthanatized at month 6. Statistically significant hemimandibular instability (p less than 0.05) persisted in all subjects throughout the study. The radiographic appearance of the joints remained unaltered; however, space asymmetry was identified in postoperative tomograms of three dogs at month 3 and four dogs at month 6. The TMJs were grossly normal at necropsy. Histologically, there were degenerative changes in articular cartilage and subchondral bone in all of the joints. The authors conclude that partial rostral hemimandibulectomy causes TMJ degeneration, as a consequence of hemimandibular instability or abnormal loading, or both.

Pathogenesis of experimental reovirus tenosynovitis in chickens: Influence of the route of infection

Four groups of specific pathogen-free, day-old chicks were infected experimentally with an avian arthrotropic reovirus strain R2 by four different routes: oral, subcutaneous, foot-pad and intra-articular. These groups were followed sequentially to study: pathological changes in the hock joints and liver; cloacal virus shedding and the presence of virus in hock joints; serological responses as determined by enzyme linked immunosorbent assay (ELISA), agar gel precipitation (AGP) and virus neutralization tests. All 4 infected groups developed arthritis or tenosynovitis with synovial hyperplasia and lymphocytic infiltration. Foot-pad and intra-articular routes of infection were found to advance the disease process by 2 to 3 weeks after infection and the more severe pathological responses seen after infection by these routes were associated with superficial degenerative changes in articular cartilage. Antibodies were detected at 2 to 3 weeks p.i. by all 3 methods, but there were no significant differences between the patterns of serological response in the infected groups. Injection into the foot-pad appears to be the most convenient and effective parenteral route of experimental infection.

Meniscal Regeneration and Its Effects on Articular Cartilage in Rabbit Knees

The incidence and size of meniscal regeneration after medial meniscectomy on the right knee and lateral meniscectomy on the left knee of 44 rabbits was observed and correlated with development of degenerative arthritis. Complete meniscal regeneration was found in 23% of medial meniscectomy knees, partial regeneration in 68%, and no regeneration in 9%. Among 44 lateral meniscectomies, only 5% had complete meniscal regeneration, and 68% had no meniscal regeneration. The remaining 27% of knees had partial regeneration. Degenerative changes of articular cartilage in the tibiofemoral joints of all knees were inversely correlated with the size of the regenerated meniscus. These observations suggest that poor results following lateral meniscectomy may be due to a lower level of meniscal regeneration and relatively poor morphological regeneration of the lateral meniscus compared to the medial meniscus.

Dose related effects of dexamethasone treatment on the ultrastructure of articular cartilage in rats.

Corticosteroid administration is known to cause degenerative changes in articular cartilage interfering with the cell metabolism of chondrocytes. The present study analyzes the ultrastructural changes in chondrocytes after systemic dexamethasone acetate treatment in relation to dosage, using a standardized morphometrical method. Five male Wistar rats of 300 g body weight in each experimental group were subjected to 3, 4 and 5 mg dexamethasone acetate by intramuscular injections of 1 mg per week. 1000 electron micrographs of single chondrocytes in the middle zone of hyaline cartilage from the knee joints were evaluated with standardized morphometry and nonparametric statistics. With increasing dexamethasone dosage the amount of rough endoplasmic reticulum and Golgi apparatus decreased. Considerably increased glycogen granula and clusters indicated a severe change in glycolytic pathways. Lysosomes duplicated in number. Degenerative changes were also manifested in lipid droplets and myeloid bodies, which, like the amount of microfilaments, exhibited a clear dosage-dependent increase under dexamethasone treatment. The ratio of dead versus living chondrocytes increased in relation to dosage up to 25% cell mortality.

Experimental Knee Instability

Utilizing a knee joint instability model for traumatic osteoarthritis, quantitative measurements of the biomechanical properties of the articular cartilage demonstrate that the cartilage deforms and that the deformation rapidly occurs within 24 hours of injury. These changes in mechanical properties may be a more sensitive indicator of early degenerative changes in articular cartilage than the ordinary histological measurements.

Role of Innominate Osteotomy in the Treatment of Congenital Dislocation and Subluxation of the Hip in the Older Child

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