Matrix formation in craniofacial cartilages of the rat. [35S]-sulfate incorporation studies

Effect of condylotomy on matrix synthesis and mineralization in the rat mandibular condylar cartilage

Little information is available about the influence of biomechanical factors on the rate of matrix synthesis and mineralization in the condylar cartilage. In an attempt to temporarily disrupt articular forces at the temporomandibular joint, bilateral condylotomies were performed on 29 day-old male Sprague-Dawley rats. Animals which underwent a similar surgical procedure except for actual condylotomy comprised a sham-operated control group; a non-operated third group served as further controls. Incorporation of [35S]-sulphate did not differ among the groups at 18 h and 2 days after condylotomy, but was significantly reduced in condylotomy animals at 7 and 14 days. Total alkaline phosphatase activity was reduced at 18 h and increased at 14 days by condylotomy, with no differences at the intermediate time intervals; similarly 45Ca-uptake was increased at the 14-day interval. Thus both matrix synthesis and mineralization of the condylar cartilage were altered in the 2 weeks after condylotomy. The changes are in general similar to those noted in other studies after a lessening or removal of articular forces from the condyle.