Morphological Observation of Process of Mouse Temporomandibular Joint Formation

Abstract

The aim of this study was to clarify the developmental mechanism of the temporomandibular joint (TMJ) cavity, using the relationship between Meckel's cartilage and the mandible to morphologically observe the process of TMJ formation in mouse fetuses. We investigated the involvement of apoptosis in the development of the mouse TMJ cavity. We attempted to 3-dimensionally clarify the developmental process of the mandible and Meckel's cartilage by observing the developmental process optically and reconstructing 3-dimensional images to observe 3-dimensional locations of the mandible and Meckel's cartilage. Formation of the upper joint cavity began on embryonal day 16, and a complete joint cavity was formed on embryonal day 18. Formation of the lower joint cavity began on embryonal day 18, and formation was almost completed on embryonal day 19. Meckel's cartilage adjacent to the mandible decreased with development of the mandible but was vestigial on embryonal day 19. The posterior region of Meckel's cartilage developed toward the posterior direction, and it was 3-dimensionally confirmed that the mandible and Meckel's cartilage were separated. Histological observation by the TUNEL method revealed the presence of solitary and diffuse apoptotic cells not only in the joint cavity, but also around the condyle.

Structure and Size-selective Permeability of the Synovial Membrane of the Temporomandibular Joint of the Mouse Measured by MR Imaging at 7T

“…Typical 2D-T 1 W imaging parameters for dynamic study were: 5 coronal slices with voxel resolution, 65 © 65 µm; slice thickness, 0.5 mm with 0.7-mm separation; a combination of TR/TE/flip angle of 100 ms/4 ms/22.5°; and image acquisition, every 45 s. Four sets of images were obtained as a control group; a contrast reagent was injected within one minute via the venous catheter with a syringe pump (TE-210, Terumo, Tokyo, Japan); and 15 sets of images were obtained every 45 s. Doses of reagents were Gd-DTPA, 200 nmol Gd/g body weight; CH3-DTPA-Gd, 200 nmol Gd/g body weight; Gd-polylysine, 127 nmol Gd/g body weight; and Gd-albumin, 7 to 10 nmol Gd/g body weight. The Gd-DTPA dose was a "double dose" used for the delayed Gd(DTPA) 2 -enhanced MR imaging. 16 Because the relaxivity of CH3-DTPA-Gd is similar to that of Gd-DTPA (personal communication from Nihon Medi-Physics), we set the dose of CH3-DTPA-Gd the same as that for the Gd-DTPA.…”

“…Inflammatory changes in the synovial membrane, cartilage, and disc characterize arthritis of the temporomandibular joint (TMJ), [1][2][3][4] and such structural changes as degradation or displacement of the disc are normally used to classify the stages of arthritis. 5 -9 Inflammation is also known to precede the development of significant structural change, 10 and joint effusion is considered an early sign of arthritis.…”

Regeneration of Mechanically Enhanced Tissue-Engineered Cartilage Based on the Decalcified Bone Matrix Framework

“…Safranin-O staining was performed to evaluate cartilage regeneration. The cartilage-specific phenotype was confirmed through collagen II staining, as previously described. − …”