title: Vestibular semicircular canal epithelium of the rat in culture on filter support: polarity and barrier properties.
abstract: The inner ear of mammals contains the vestibular apparatus which is involved in the maintenance of posture and balance. The tubular structure of the apparatus is bathed by the potassium-rich endolymph and sodium-rich perilymph in the luminal and abluminal compartments, respectively. The luminal compartment is lined by a continuous epithelium with islets of receptor organs, which separates the luminal from the abluminal compartment. The present work focuses on the epithelium, without the receptor organs, and shows that it can be reconstituted in culture. The epithelium from 4-day-old Wistar rats was grown on microporous membranes. High transepithelial electrical resistances (4000-6000 Omega.cm2) were achieved after 4-8 days in culture. The epithelium was characterized by the presence of cytokeratin, ZO-1 protein, occludin, and the presence of tight junctions and kinocilia. The transepithelial resistance of the cell monolayer withstood endolymph/perilymph dual bathing when the apical pole of the cells was in contact with endolymph, but collapsed in the reverse configuration. Weak but statistically highly significant basal to apical rubidium (86Rb) transport was observed. These findings show that this epithelium maintains its in vivo polarity and could enhance the potassium composition of endolymph up to maturity. This new culture model, in which dual bathing is possible, should enable further in vitro studies of the sensory vestibular epithelia.
authors.affiliation: Université Montpellier II, INSERM U.432, CC089, Neurobiologie et développement du système vestibulaire, Place Eugène Bataillon, F-34095 Montpellier cedex 5, France. pmilhaud@crit.univ-montp2.fr
authors.forename: P G
authors.initials: PG
authors.lastname: Milhaud
authors.forename: M T
authors.initials: MT
authors.lastname: Nicolas
authors.forename: S
authors.initials: S
authors.lastname: Bartolami
authors.forename: M T
authors.initials: MT
authors.lastname: Cabanis
authors.forename: A
authors.initials: A
authors.lastname: Sans
mesh_terms: D000818:Animals; D016764:Cell Polarity; D002478:Cells, Cultured; D017097:Electric Impedance; D004847:Epithelial Cells / Q000502:physiology / Q000648:ultrastructure; D007633:Keratins / Q000032:analysis; D008196:Lymph; D008565:Membrane Proteins / Q000032:analysis; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D062793:Occludin; D010750:Phosphoproteins / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D012665:Semicircular Canals / Q000502:physiology*; D019108:Tight Junctions / Q000648:ultrastructure; D013997:Time Factors; D062826:Zonula Occludens-1 Protein
chemical_list: D008565:Membrane Proteins; D062793:Occludin; C568987:Ocln protein, rat; D010750:Phosphoproteins; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; D007633:Keratins