Study on transplanted auricular cartilage after removal of articular disc or condylar head of the temporomandibular joint

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 10671877
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Surgical dentistry
• Research Institution: Shimane Medical University
• Principal Investigator: YOSHIMURA Yasuro School of medicine, Shimane Medical University, professor, 医学部, 教授 (50093480)
• Co-Investigator(Kenkyū-buntansha): MATSUDA Shuji School of medicine, Shimane Medical University, research associate, 医学部, 助手 (80239029) ; KINGETSU Akira School of medicine, Shimane Medical University, medical staff
• Project Period (FY): 1998 – 1999
• Keywords: TMJ (Temporomandibular joint) / Condylar head removal / Auricular cartilage transplantation / Cytokines

Research Abstract

This study was done to investigate the relationship between occlusal impairment and loss of vertical dimension due to condylar removal, and to investigate the use autologous auricular cartilage for prevention of the occlusal impairment.
We used 102 adult male ICR mice in three separate experimental groups for 2 years : condylectomy only ; condylectomy plus auricular cartilage transplantation ; and, sham operation. The treatments were performed using microsurgical microscopy. The mice were sacrificed 38 to 191 days after the operations. We investigated their occlusal abnormalities by macroscopic examination. Morphological changes of transplanted auricular cartilage and the opposite temporomandibular joint (TMJ) were also studied by hematoxylin-eosin stain and immunohistochemical examinations.
The following results were obtained :
1. Macroscopic findings : Occlusal impairment was observed in at least 5 of the 49 mice which had been successfully treated. Their mandibular bones shifted to the operated side and incisal contact was lost completely. This change brought about an inability to feed naturally and thus the eventual death of the mouse.
2. Histological findings : Transplanted auricles seemed to change their positions because of a lack of fixation and mandibular movement, that is they slipped out laterally from the TMJ in many cases.
3. Immunohistochemical findings : Cells facing the articular cavity and located near the articular surface of the fossa and condyle showed positive reactions to transforming growth factors-β (TGF-β), while chondrocytes under them generally revealed negative staining for TGF-β. Transplanted auricular chondrocytes presented slight positiveness or negative for TGF-β.
As for the fibroblast growth factor-2 (TGF-2), cells lining the articular cavity, the cells under them and chondrocytes were all positive for TGF-2 ; however, the first category showed the strongest staining of the 3 different cell categories. Transplanted auricular chondrocytes presented weak partial staining.
Bone morphogenetic protein (BMP) was generally not observed in the above mentioned cells and auricular choudrocytes.
Laminin was not demonstrated in any cells comprising the articular structures. Further, transplanted auricular cells showed no staining.