An osteoarthritis is regarded as a degenerative lesion resulting from mechanical trauma of the joint. The mild injury of the srticular cartilage is easily regenerated, but regenerating process is very slow in the severe injury or injury in aged
persons.
The trauma makes articular cartilage injury by releasing proteolytic enzyme and collagenase. The progress of osteoarthritis are various according to the severity of trauma and age.
To investgate causes of osteoarthritis, histological, immunohistochemical and electron microscopical studies were performed in the young and adult rats which were received intra-articular injection of collagenase.
@ES The results were as follows.
@EN 1. The amount of cartilage was decreased and hypertrophic zone was replaced to bony tissue. Tidemark was indentified. The above findings was prominent in the groups of 4 weeks and 8 weeks.
2. Immunohistochemical stain for concanavalin A revealed positive reaction in the chondrocytes and matrix, and soybean agglutinin in matrix. Positive reaction for proteoglycan was identified in the chondrocytes of upper zone.
3. In ultrastructural findings, the chondrocytes were frequently arranged in the clusters, degenerated and necrotic chondrocytes were noted especially in the deep zone. The degenerted chondrocytes had a prominent nuclear fibrous lamina and
numerous
filaments. They also contained a dilated or vesiculated rough endoplasmic reticulum, lysosome-like bodies, a few of vacuoles and vesicles. Numerous matrix vesicles and lipid globules derived from necrotic chondrocytes were identified in the
region
adjoining the calcified cartilege.
The collagdenase made articular cartilage be damaged by disturb the matrix, and osteoarthritis was developed. Aging is suggested to be a causative factor of osemoarthritis.
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