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

Abstract

Purpose: We analyzed the anatomical structure of the temporomandibular joint (TMJ) and molecular weight dependency of synovial membrane permeability in mice using 7-tesla magnetic resonance (MR) imaging.Methods: We obtained 3-dimensional (3D) T 1 -weighted gradient echo (3D-T 1 W) and 3D T 2 -weighted rapid acquisition with relaxation enhancement (3D-T 2 W RARE) MR images of the TMJ of male C57BL6 mice with voxel resolution of 65 µm. Two-dimensional (2D) T 1 w images were measured every 45 s before and after bolus intravenous (IV) injection of contrast reagents: gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA; 0.5 kDa); oligomer-based contrast agent (CH3-DTPA-Gd; 2.1 kDa); gadolinium-labeled polylysine (Gd-polylysine; 10 kDa); and gadolinium-labeled albumin (Gd-albumin; 74 kDa).Results: T 1 W images depicted the temporal bone and mandibular condyle as regions with lower signal intensity and the disc as a region of intermediate intensity. In the Gd-DTPA-enhanced T 1 W and T 2 W images, the articular disc could be identified as a region with lower signal intensity than that of the upper and lower joint cavities. After IV injection of Gd-DTPA or CH3-DTPA-Gd, the signal intensity of the joint cavities increased within 10 min, but this increase was not shown with Gd-polylysine and Gd-albumin.Conclusion: The structural findings obtained by MR imaging agreed with those obtained by hematoxylin-eosin staining under light microscopy. Contrast-enhanced MR imaging suggested that smaller (<2.1 kDa) but not larger (>10 kDa) molecules can permeate the synovial membrane. Our results suggest the utility of MR imaging for analyzing the structure of the TMJ as well as permeability of the synovial membrane.

Rat mandibular condyle and fossa grew separately then unified as a single joint at 20 days old, which was the weaning age

“…In a previous report, the articular disc of rodent TMJs were depicted using contrast-enhanced MRI [8,9]. In the present study, the articular disc was also observed without contrast reagent and depicted with the reagent in P20 rats (Fig.…”

“…Gd-DTPA (200 nM Gd/ g body weight) was used for the dynamic study. MR images of the TMJ were obtained with a 7-tesla microimaging system (AVANCE III, Bruker Biospin, Ettlingen, Germany) with ParaVison operating software (version 5.1, Bruker Biospin), as previously described [8,9]. The coronal plane image was defined as a slice vertical to the base of the brain and vertical to the midline.…”

“…These MR images were consistent with the results of hematoxylin-eosin (H-E) staining under light microscopy. Moreover, the TMJ coronal and sagittal planes were defined for MRI in rodents that weighed less than 100 g [9]. In addition, the molecular weight dependency of synovial membrane permeability in mice TMJ was characterized.…”

“…In addition, the molecular weight dependency of synovial membrane permeability in mice TMJ was characterized. Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) is a useful reagent for identifying the articular disc in rats [8] and mice [9]. In clinical studies, MRI of the human TMJ has been used to observe specific areas or targets, such as the anterior displacement or structural degradation of the disc [10,11].…”

Repeated Live Imaging in the Temporomandibular Joint of an Anterior Crossbite Mouse Model Using a 7T Magnetic Resonance Device

“…Computed tomography (CT) and magnetic resonance (MR) imaging are used in clinical practice and are often applied to determine the treatment strategies and evaluate their effects. There are only few studies which have radiologically evaluated the results of histopathological findings using animal disease models (4,5). Thus, the relationship between actual pathological changes and radiological findings therefore remains unclear.…”