가토 하악 과두 동종이식시 냉동보존제가 과두 연골에 미치는 영향에 관한 실험적 연구

Experimental studies on cryopreservation effects in condylar allografts in rabbits

Loss of function in the Temporomandibular joint (TMJ) arising from congenital disorders, tumors, trauma, and various arthritides has long been a challenge to the reconstructive surgeon. Although reconstruction to date has been performed with various prosthetic devices or autogenous costochondral grafts, these procedures have the potential of complication and morbidity from the harvest procedures. There have been many animal transplant studies of specific cryogenically preserved allografts joint and several extensive clinical studies of human joints transplantation in the international orthopedic literature. However, the use of preserved allogeneic mandibular condyles (bone and cartilaginous articular surface) for reconstruction of the TMJ has not been described. Various methods of preservation of allogeneic condyle have been introduced to enhance the storage and sterility, and to remove antigenecity. Current methods of articular cartilage chondrocytes preservation include refrigeration (-4℃), deep-freezing (-70℃), and cryopreservation. An experimental procedure was designed to determine the effects of cryopreservative agents with deep frozen and freeze-dried allogeneic condylar graft by pretreatment with DMSO (Dimethyl sulphoxide) and Glycerol. The aim of this study was to compare the microscopic differences between deep frozen and freeze dried allogeneic condyle grafts pretreated with DMSO and Glycerol, and to produce a satisfactory method of chondrocytes preservation, as a preliminary in preparation for widespread application in Wonkwang University bone banking procedures. Comparison were made among four types of Temporomandibular joint transplants in rabbits : 1) Deep-frozen with DMSO, 2) Freeze-dried with DMSO, 3) Deep-Frozen with Glycerol, and 4) Freeze-dried with Glycerol. The results of the study were; 1. Inflammatory cell infiltration of articular surface was most severe in the Freeze-dried with Glycerol group and was least severe in the Deep-frozen with DMSO groups. 2. Viability of bone below the subchondral zone showed few differences among four experimental groups. But the Glycerol groups were less viable than the DMSO groups. 3. Degenerative change of condylar cartilage appeared after 1 week and disappeared after 6 weeks. The most intense change was in the Freeze-dried with Glycerol group. 4. Maturing of condylar cartilage began at 2 weeks and there were no differences between Freeze-dried and Deep-frozen groups. But DMSO groups appeared more than Glycerol groups. 5. There were no differences between the groups in the degree of endochondral ossification after 2 weeks. This data hold out great promise for the future development of a frozen-joint bank. Our studies showed that Deep-frozen cryopreservation pretreated with DMSO can offer a more preservation method of the osteochondral allografts.