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.