Detection of synovial macrophages in the joint capsule of dogs with naturally occurring rupture of the cranial cruciate ligament.
OBJECTIVE
To test the hypotheses that the densities of macrophages in the synovial membranes and capsules of stifle joints in dogs with ruptured cranial cruciate ligaments are greater than those of normal joints and that those densities in affected joints are positively correlated with the chronicity and severity of the disease.


METHODS
17 dogs with naturally occurring rupture of the cranial cruciate ligament and 5 healthy control dogs.


METHODS
All dogs underwent orthopedic and radiographic evaluations. In affected dogs, duration of clinical signs was used as an indicator of disease chronicity and the severity of osteoarthritis in the stifle joint was determined radiographically. Joint capsule specimens were evaluated histologically; macrophages, interleukin-6, and tumor necrosis factor-alpha were identified by use of immunocytochemical techniques.


RESULTS
Compared with unaffected joints, macrophage density was increased in all affected joints. Duration of disease was significantly associated with radiographic severity of osteoarthritis and synovial macrophage density. Synovial macrophage density was significantly associated with severity of osteoarthritis and with the presence of interleukin-6 and tumor necrosis factor-a.


CONCLUSIONS
Results suggest that synovial macrophages may be involved in the development of pathologic changes (including osteophyte formation) in the stifle joints of dogs with osteoarthritis secondary to rupture of the cranial cruciate ligament. Determination of the importance of synovial macrophages in the development of changes in osteoarthritic joints may result in new treatment strategies that involve elimination of the deleterious effects of those cells.
Klocke
Nathan W
NW
Department of Veterinary Clinical Sciences, College of Science, Purdue University, West Lafayette, IN 47907, USA.
Snyder
Paul W
PW
Widmer
William R
WR
Zhong
Wenxuan
W
McCabe
George P
GP
Breur
Gert J
GJ
D000818:Animals; D000070598:Anterior Cruciate Ligament Injuries; D004283:Dog Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D004285:Dogs; D007150:Immunohistochemistry / Q000662:veterinary; D015850:Interleukin-6 / Q000378:metabolism; D017746:Joint Capsule / Q000473:pathology*; D008264:Macrophages / Q000378:metabolism*; D010003:Osteoarthritis / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D011859:Radiography; D012422:Rupture, Spontaneous / Q000150:complications*; D013264:Stifle / Q000000981:diagnostic imaging; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha