HISTOPATHOLOGICAL FINDINGS ON ULCERATIVE LESIONS OF CARPAL AND TARSALJOINTS IN JAPANESE BLACK CATTLE

In order to determine the pathogenesis of ulcerative lesions of the ar ticular cartilages in Japanese Black cattle, tissue samples of the ulc erative lesion, marginal portion of the ulcer, macroscopically normal portions and synovial membranes were histopathologically examined by l ight microscopy, scanning electron microscopy and contact microradiogr aphy. The results are summarized as follows: (1) In the ulcerative les ions, degeneration and complete destruction of articular cartilage and its replacement with a proliferation of myelogenic connective tissue were observed. (2) In macroscopically normal portions, fissures of the articular surface and changes of the trabecular pattern in subchondra l bone were present. (3) In the marginal portions of the ulcerative le sions, evidences of the repair process such as connective tissue growt h from subchondral bones and articular cartilages were seen. (4) In sy novial membranes, no pathological findings were observed. And (5) amon g the above mentioned changes, no inflammatory findings were seen. In conclusion, the ulcerative lesions of bovine articular cartilage may b e regarded as the early stage of osteochondrosis to osteoarthrosis sin ce the findings such as noninflammatory destruction or degeneration an d remodeling of the joints are characteristics of the latter.