OBJECTIVETo investigate the histological changes in the vestibular endorgans of Smad4 gene conditional knockout mice and to explore the influence of the Smad4 gene on vestibular development.

METHODSHistological changes of periphery vestibular organs in inner ear of Smad4 conditional knockout mice were investigated by frozen sections, immunofluorescence, confocal microscopy, scanning electron microscopy and transmission electron microscopy.

RESULTSThere was no Smad4 expression in the inner ear cartilage capsule of Smad4-/- mice. In Smad4+/- mice, Smad4 expression in the same cartilage capsule was positive, and it was strong positive in Smad4+/+ mice. Smad4 expression in vestibular sense epithelium, crista ampullaris and macula, was positive. And no difference was found among these three genotypes. Studying at scanning electron microscopy and transmission electron microscopy levels and anti-filament immunofluorescence showed that no pathological changes were observed in all the three genotype mice.

CONCLUSIONAlthough the Smad4 gene was knockout effectively in the auricular cartilage capsule of Smad4 conditional knockout mice,the histological changes of Smad4 conditional knockout mice in vestibulum auris internal were slightly.

Animals ; Ear, Inner ; anatomy & histology ; pathology ; Genotype ; Mice ; Mice, Knockout ; Smad4 Protein ; genetics ; Vestibule, Labyrinth ; anatomy & histology ; pathology

OBJECTIVE: To compare the use of 3D driven equilibrium (DRIVE) imaging with 3D balanced fast field echo (bFFE) imaging in the assessment of the anatomic structures of the internal auditory canal (IAC) and inner ear at 3 Tesla (T). MATERIALS AND METHODS: Thirty ears of 15 subjects (7 men and 8 women; age range, 22-71 years; average age, 50 years) without evidence of ear problems were examined on a whole-body 3T MR scanner with both 3D DRIVE and 3D bFFE sequences by using an 8-channel sensitivity encoding (SENSE) head coil. Two neuroradiologists reviewed both MR images with particular attention to the visibility of the anatomic structures, including four branches of the cranial nerves within the IAC, anatomic structures of the cochlea, vestibule, and three semicircular canals. RESULTS: Although both techniques provided images of relatively good quality, the 3D DRIVE sequence was somewhat superior to the 3D bFFE sequence. The discrepancies were more prominent for the basal turn of the cochlea, vestibule, and all semicircular canals, and were thought to be attributed to the presence of greater magnetic susceptibility artifacts inherent to gradient-echo techniques such as bFFE. CONCLUSION: Because of higher image quality and less susceptibility artifacts, we highly recommend the employment of 3D DRIVE imaging as the MR imaging choice for the IAC and inner ear.
Adult ; Aged ; Cochlea/anatomy & histology ; Ear, Inner/*anatomy & histology ; Female ; Humans ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging/*methods ; Male ; Middle Aged ; Semicircular Canals/anatomy & histology ; Vestibule, Labyrinth/anatomy & histology