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Effects of ovariectomy and estrogen-replacement after ovariectomy on the young rat temporomandibular joints
P22-3 Temporomandibular joint & Pathology (cyst and others) P22-3 Temporomandibular joint & Pathology (cyst and others) 1. Histology and Immunohistochemistryof TemporomandibularJoint (TMJ) Synovitis in Rats Inducedby Condylar Hypermobility
Kawakami, J., Muto, T., Uchida, N.., Kanazawa, M. Departments of Oral and Maxillofacial Surgery, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan To induce traumatic TMJ synovitis by condylar hypermobility, an intentional 20-mm-wide opening of the mouth was performed under general anesthesia with ether, using 12 Wistar male rats aged 8 weeks and weighing 100 to 150 g. This procedure was repeated 10 times sequentially for 10 days, having no influence on body weight increase in any of the experimental animals. Injury-induced synovial changes were observed histologically and immunohistochemically 5 days, 2 weeks, 4 weeks and 6 weeks after the treatment. Pathological changes were mainly observed in the anterior synovium of the upper joint compartment; further findings were as follows: 1. The initial reaction to traumatic injury in the synovial membrane was a proliferation of surface cells and an increase in capillary hyperemia. 2. Fibrin deposits on the surfaces of the inflamed synovial membranes were observed, and fibrin between closely opposed synovial membranes indicated fibrinous adhesion. 3. There was a gradual change from fibrinous adhesion to fibrous adhesion. In addition, we are presently investigating the synovial lining cells (macrophage-like cells) immunohistochemically utilizing monoclonal antibodies against rat macrophages (ED1, ED2 and ED3). Thus these findings will be presented together.
2. Effects of Ovariectomy and Estrogen-Replacement after Ovariectomy on the Young Rat TemporomandibularJoints
Yasuoka, T., Okuda, T., Nakashima, M., Tatematsu, N. Department of OMF Surgery, Gifu Univ. Sch. of Med., G!fit, Japan Four-week-old female Wister rats were ovariectomized and sacrificed at 1, 2, 4, and 8 weeks postoperatively. Histomorphometric study of the TMJ was performed with a synchronous system. The serum levels of estrogen, calcitonin, and C-terminus parathyroid hormone were also determined. Administration of 17b-estradiol was performed to substitute for estrogen after ovariectomy. In the sham-operated group, the serum levels of estrogen and calcitonin increased with age. An increase of the bone volume, with a corresponding increase of the osteoid surface,
201
was observed at 12 weeks. Thickness of the articular soft tissue was decreased with advancing age. In the ovariectomized animals, serum estrogen was not detected. A biphasic change of parathyroid hormone level, with decreases at 1 and 2 weeks postoperatively and increases at 4 and 8 weeks postoperatively, was noted, whereas a constant level of calcitonin was observed. Thickness of the articular soft tissue was increased in the anterior and central portions of the condyle at 1, 2, and 4 weeks after the ovariectomy, whereas there were no appreciable changes in the posterior portion. The bone volume was decreased during the experiment, particularly in the posterior portion. An osteophyte in the anterior region was also observed 8 weeks postoperatively. In the estrogen-replaced group after ovariectomy, most of the articular soft tissue and bone histomorphometric parameters were recovered. However, an increase of bone volume was found with concomitant increase of osteoid surface and decrease of quiescent surface in the central portion at 2 weeks postoperatively. Estrogen deficiency during puberty predisposes to alterations of the TMJ through changes in serum calcitonin and parathyroid hormone levels. Exogenous estrogen may recover most of the parameters of TMJ remodeling after ovariectomy.
3. The Expression of Tenascin mRNA in Surgically Removed Specimens of the Human TemporomandibularJoint
Yoshida, 11., Fujita, S., lizuka, T. Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kyoto University, Kyoto, Japan Tenascin (TN) is an extracellular matrix (ECM) glycoprotein which is reportedly involved in wound healing in most tissues. We examined the expression of tenascin m R N A in the human temporomandibular joint (TMJ) disc and the synovial membrane in 29 human TMJ samples (internal derangements, ankylosi~ and control) by in situ hybridization. In all of the specimens, the restricted distribution of immunoreactive TN was observed in the walls of blood vessels, in the perineurium, and at the surface of the TMJ disc. Intense staining for TN was shown in the stroma of hypertrophic synovial membranes, particularly at the surface of severe hypertrophic synovial membranes with inflammation, proliferation, irregular lining structures and new growth of capillaries. Furthermore, in situ hibridization of freshly obtained TMJ joint discs and synovial membranes demonstrated that TN m R N A is expressed in synovial cells as well as flbroblasts, and endothelial cells. The expression of TN m R N A was most evident in synovial cells. In conclusion TN is produced by synovial cells, fibroblasts, and endothelial cells in affected human TMJ.
Kawakami, J., Muto, T., Uchida, N.., Kanazawa, M. Departments of Oral and Maxillofacial Surgery, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan To induce traumatic TMJ synovitis by condylar hypermobility, an intentional 20-mm-wide opening of the mouth was performed under general anesthesia with ether, using 12 Wistar male rats aged 8 weeks and weighing 100 to 150 g. This procedure was repeated 10 times sequentially for 10 days, having no influence on body weight increase in any of the experimental animals. Injury-induced synovial changes were observed histologically and immunohistochemically 5 days, 2 weeks, 4 weeks and 6 weeks after the treatment. Pathological changes were mainly observed in the anterior synovium of the upper joint compartment; further findings were as follows: 1. The initial reaction to traumatic injury in the synovial membrane was a proliferation of surface cells and an increase in capillary hyperemia. 2. Fibrin deposits on the surfaces of the inflamed synovial membranes were observed, and fibrin between closely opposed synovial membranes indicated fibrinous adhesion. 3. There was a gradual change from fibrinous adhesion to fibrous adhesion. In addition, we are presently investigating the synovial lining cells (macrophage-like cells) immunohistochemically utilizing monoclonal antibodies against rat macrophages (ED1, ED2 and ED3). Thus these findings will be presented together.
2. Effects of Ovariectomy and Estrogen-Replacement after Ovariectomy on the Young Rat TemporomandibularJoints
Yasuoka, T., Okuda, T., Nakashima, M., Tatematsu, N. Department of OMF Surgery, Gifu Univ. Sch. of Med., G!fit, Japan Four-week-old female Wister rats were ovariectomized and sacrificed at 1, 2, 4, and 8 weeks postoperatively. Histomorphometric study of the TMJ was performed with a synchronous system. The serum levels of estrogen, calcitonin, and C-terminus parathyroid hormone were also determined. Administration of 17b-estradiol was performed to substitute for estrogen after ovariectomy. In the sham-operated group, the serum levels of estrogen and calcitonin increased with age. An increase of the bone volume, with a corresponding increase of the osteoid surface,
201
was observed at 12 weeks. Thickness of the articular soft tissue was decreased with advancing age. In the ovariectomized animals, serum estrogen was not detected. A biphasic change of parathyroid hormone level, with decreases at 1 and 2 weeks postoperatively and increases at 4 and 8 weeks postoperatively, was noted, whereas a constant level of calcitonin was observed. Thickness of the articular soft tissue was increased in the anterior and central portions of the condyle at 1, 2, and 4 weeks after the ovariectomy, whereas there were no appreciable changes in the posterior portion. The bone volume was decreased during the experiment, particularly in the posterior portion. An osteophyte in the anterior region was also observed 8 weeks postoperatively. In the estrogen-replaced group after ovariectomy, most of the articular soft tissue and bone histomorphometric parameters were recovered. However, an increase of bone volume was found with concomitant increase of osteoid surface and decrease of quiescent surface in the central portion at 2 weeks postoperatively. Estrogen deficiency during puberty predisposes to alterations of the TMJ through changes in serum calcitonin and parathyroid hormone levels. Exogenous estrogen may recover most of the parameters of TMJ remodeling after ovariectomy.
3. The Expression of Tenascin mRNA in Surgically Removed Specimens of the Human TemporomandibularJoint
Yoshida, 11., Fujita, S., lizuka, T. Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kyoto University, Kyoto, Japan Tenascin (TN) is an extracellular matrix (ECM) glycoprotein which is reportedly involved in wound healing in most tissues. We examined the expression of tenascin m R N A in the human temporomandibular joint (TMJ) disc and the synovial membrane in 29 human TMJ samples (internal derangements, ankylosi~ and control) by in situ hybridization. In all of the specimens, the restricted distribution of immunoreactive TN was observed in the walls of blood vessels, in the perineurium, and at the surface of the TMJ disc. Intense staining for TN was shown in the stroma of hypertrophic synovial membranes, particularly at the surface of severe hypertrophic synovial membranes with inflammation, proliferation, irregular lining structures and new growth of capillaries. Furthermore, in situ hibridization of freshly obtained TMJ joint discs and synovial membranes demonstrated that TN m R N A is expressed in synovial cells as well as flbroblasts, and endothelial cells. The expression of TN m R N A was most evident in synovial cells. In conclusion TN is produced by synovial cells, fibroblasts, and endothelial cells in affected human TMJ.