Ultrastructural study of synovitis induced by trauma to the rat temporomandibular joint (TMJ).
BACKGROUND
Electron microscopy was used to examine the histologic effect of trauma on the rat temporomandibular joint synovial membrane.


METHODS
Trauma to the TMJ in male Wister rats (100-200 g) was introduced through repeated forced condylar hypermobility. Ultrastructural observations were made 5 days and 6 weeks after the trauma.


RESULTS
The early response of the synovial membrane was synovial hyperplasia, type A synovial cell loss, dilation of the r-ER in the type B synovial cells and fibrin deposition on the synovial surfaces. The late response included degeneration of synovial cells with swollen mitochondria and cell projections, and cell fragmentation. Large amount of fibrin deposition on opposing surface layers was also noticed.


CONCLUSIONS
The type A cell loss and fibrin deposition followed by the occurrence of fibrinous materials at opposing surface layers of the synovial membrane suggest that traumatic synovitis causes synovial adhesions.
Muto
Toshitaka
T
First Department of Oral and Maxillofacial Surgery, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan.
Shigeo
Kimiharu
K
Kanazawa
Masaaki
M
Irie
Kazuharu
K
Yajima
Toshihiko
T
Kaku
Tohru
T
D000818:Animals; D018870:Endoplasmic Reticulum, Rough / Q000473:pathology; D024022:Fibrillar Collagens / Q000032:analysis; D005337:Fibrin / Q000032:analysis; D006965:Hyperplasia; D007593:Joint Instability / Q000150:complications; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013583:Synovial Membrane / Q000293:injuries* / Q000473:pathology / Q000648:ultrastructure*; D013585:Synovitis / Q000209:etiology / Q000473:pathology*; D013704:Temporomandibular Joint / Q000293:injuries*; D000267:Tissue Adhesions / Q000209:etiology
D024022:Fibrillar Collagens; D005337:Fibrin