Immunohistochemical Localization and Distribution of Proliferating Cell Nuclear Antigen in the Rabbit Mandibular Condyle Following Experimental Induction of Anterior Disk Displacement

ABSTRACT

The purpose of the present study was to identify proliferating cells in control versus experimental condyles two weeks following experimental Induction of anterior disk displacement (ADD) in the rabbit craniomandibular joint (CMJ). The right joint of 15 rabbits was exposed surgically and all diskal attachments were severed except for the posterior attachment. The disk was then repositioned anteriorly and sutured to the zygomatic arch. The left joint served as a sham-operated control. Ten additional joints were used as nonoperated controls. Mandibular condyles were excised two weeks following surgery and processed for proliferating cell nuclear antigen (PCNA) immunostaining. In control and sham operated condyles, PCNA was localized in the nuclei of chondroblasts of the reserve cell layer, chondrocytes of the upper hypertrophic layer and bone marrow cells of the subchondral bone. In contrast to control joints, the PCNA positive cells of the experimental joints were located throughout the osteoarthritic condylar cartilage. In addition, the percentage of PCNA positive cells of the osteoarthritic condylar cartilage was statistically significantly higher when compared to the control group, p < 0.05. It was concluded that surgical induction of ADD in the rabbit CMJ leads to an increase in mitosis of chondrocytes, which lead to cell proliferation and subsequent hyperplasia of the condylar cartilage.

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Notes on contributors

Mohamed M. Sharawy

Dr. Mohamed Sharawy received his B.D.S. in 1962, his oral surgery training in 1965 from the Faculty of Oral and Dental Medicine at Cairo University in Egypt and his Ph.D. degree in 1970 from the University of Rochester in Rochester, New York. His is currently Professor and Director of Anatomy in the Department of Oral Biology, Professor of Oral Biology, and Professor of Oral and Maxillofacial Surgery at the Medical College of Georgia, School of Dentistry. Dr. Sharawy is also Professor of Anatomy in the school of Graduate studies and Director of the Craniofacial Research section of the Medical College of Georgia Dental Research Center.

Ayman M. Ali

Dr. Ayman M. Ali received his Ph.D. in 1994 and his research fellowship in 1995 from the Medical College of Georgia and his D.M.D. in 1997 from the University of Pennsylvania. He is currently an Assistant Professor of Oral Biology and Maxillofacial Pathology and also in private practice.

Won-Seok Choi

Dr. Won-Seok Choi received his D.D.S. degree from the University of South Korea and his Ph.D. degree and orthodontic residency in 1996 from the Medical College of Georgia. He is currently in practice limited to Orthodontics in South Korea.