Journal of Dental Research, Vol 71, 1292-1297, Copyright © 1992 by International & American Associations for Dental Research Online Journals
Alterations in rat condylar cartilage following discectomy
R. J. Hinton
Department of Anatomy, Baylor College of Dentistry, Dallas, Texas 75246.
The purpose of this study was to examine the effect of unilateral
extirpation of the articular disc of the temporomandibular joint on
selected metabolic and compositional characteristics of the condylar
cartilage. Unilateral discectomy was performed in one group of growing
(28-day-old) rats, while another group received only unilateral arthrotomy.
The effect of the discectomy procedure was assessed by comparison of ratios
of the operated to unoperated sides in the discectomy and arthrotomy
groups. Total uronic acid content (micrograms/mg dry tissue wt) of the
condylar cartilage and [35S]-sulfate incorporation (dpm/micrograms uronic
acid) into the condylar cartilage were decreased in discectomy-group
animals at nine, 16, and 28 days following surgery, while hydration of the
cartilage was increased in discectomy animals at both 16 and 28 days
post-surgery. Wet and dry tissue weights of the cartilage were dramatically
increased in discectomy-group animals at all post-operative intervals.
These metabolic and compositional changes were accompanied by pronounced
structural alterations in the cartilage, including chondrocyte clustering
and tears parallel to the articular surface. With the exception of
[35S]-sulfate incorporation, the changes demonstrated in the condylar
cartilage following discectomy were similar to early osteoarthritic
alterations reported in limb articular cartilage following partial
meniscectomy or cruciate ligament resection.