Fetal jaw movement affects development of articular disk in the temporomandibular joint

Abstract

Previous studies suggest that jaw movement is an important factor in the development of cartilage in the temporomandibular joint during the prenatal and postnatal periods. In the present study, the effects of fetal jaw movement on the articular disk were studied in mice by restraining the opening movement of the mouth using the mouse exo utero development system. At embryonic day 18.5, the articular disk was reduced in size in the embryos whose maxilla and mandible were sutured (sutured group) and there were changes in the cellular morphology of the mesenchymal cells in the disk. The volume of the articular disk, the total number of cells and the number of 5-bromo-2'-deoxyuridine-positive cells in the articular disk were significantly lower in the sutured group than in the non-sutured control group. Our data revealed that fetal jaw movement affects the development of the articular disk in the temporomandibular joint.

Mathematical Analysis of Mandibular Morphogenesis by Micro‐CT‐Based Mouse and Alizarin Red S‐Stained‐Based Human Studies During Development

“…After the operation, the fetuses together with the uterus were placed back in the abdominal cavity of the dam, and the incision on the abdominal muscle was sutured closed with 3-or 4-0 silk line; incision of the abdominal skin was closed by autosuture (MikRon 9 mm Autoclip Applier), and were allowed to develop exo utero till E18.5. As in our several previous studies (Hatta et al, 1994(Hatta et al, , 2002(Hatta et al, , 2004Habib et al, 2005Habib et al, , 2007Jahan et al, 2010), we observed that the exo utero surgery as described caused no general growth retardation, and neither the CRL, BW, nor the mandibular morphology of the E18.5 sham-operated fetuses were significantly different from those of the E18.5 in utero normal fetuses. Therefore, we here show only the results of sham-operated fetuses, and not those of in utero normal fetuses, as the control.…”

“…Exo utero surgery was performed as described previously (Hatta et al, 1994(Hatta et al, , 2002(Hatta et al, , 2004Habib et al, 2005Habib et al, , 2007Udagawa et al, 2006;Yamada et al, 2008;Jahan et al, 2010). Briefly, at E15.5, the pregnant dams were anesthetized with 50 mg/kg BW of pentobarbital.…”

Response of knee fibrocartilage to joint destabilization

“…The expanded tissue has features of the condylar fibrocartilage of the temporomandibular joint (TMJ) with a thickened fibrocartilaginous zone containing cells that express the Col3.6blue reporter and ColXred cells in the deeper regions near the site of cartilage mineralization 11 . The condylar cartilage of the TMJ originates from periosteal cells 31 and is particularly responsive to shearing forces 32 and thus observing a similar response in other periosteal structures might be anticipated. The expansion was exceptionally prominent on the medial condyle of the tibia in which the central region was transitioning to an osteophyte as evidenced by the accumulation of strong Col3.6blue osteoblasts, osteoclasts and bone marrow.…”

Morphological Observation of Process of Mouse Temporomandibular Joint Formation

“…Although a number of reports have investigated the developmental process of the TMJ in various animals 7,9,11,14) , including human 2,4,15,16) , no view of the mouse TMJ has been established. In particular, in mouse, although the developmental period of the lower joint cavity showed variation, development occurred after birth in many studies [5][6][7] .…”

“…Moreover, to our knowledge, no studies to date have clarified the developmental mechanism of the TMJ cavity. Many in vivo and in vitro studies have investigated TMJ formation, with some including an analysis of the involvement of homeobox genes 2,9,11) . The relationship between Meckel's cartilage and the cells involved in jaw bone formation remains to be clarified.…”