title: Two-photon microscopy of the mouse cochlea in situ for cellular diagnosis.
abstract: Sensorineural hearing loss is the most common type of hearing loss worldwide, yet the underlying cause is typically unknown because the inner ear cannot be biopsied today without destroying hearing, and intracochlear cells have not been imaged with resolution sufficient to establish diagnosis. Intracochlear imaging has been technologically challenging because of the cochlea's small size and encasement in bone. We report, for the first time, imaging of the mouse cochlea in situ without exogenous dyes, through a membranous round window, using a near-infrared femtosecond laser as the excitation and endogenous two-photon excitation fluorescence (TPEF) and second harmonic generation as the contrast mechanisms. We find that TPEF exhibits strong contrast allowing cellular, and even subcellular resolution, and detection of specific, noise-induced pathologic changes. Our results demonstrate that the round window provides a useful access to the cochlea through the middle ear, and they motivate future development of a new and efficient diagnostic tool based on two-photon micro-endoscopy.
authors.affiliation: École Polytechnique Fédérale de Lausanne, School of Engineering, Optics Laboratory, BM 4.107, Station 17, CH-1015 Lausanne, Switzerland.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.forename: Ye
authors.initials: Y
authors.lastname: Pu
authors.forename: Chia-Lung
authors.initials: CL
authors.lastname: Hsieh
authors.forename: Cheng Ai
authors.initials: CA
authors.lastname: Ong
authors.forename: Demetri
authors.initials: D
authors.lastname: Psaltis
authors.forename: Konstantina M
authors.initials: KM
authors.lastname: Stankovic
mesh_terms: D000818:Animals; D006198:Hair Cells, Auditory / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000473:pathology*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D051379:Mice; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D009925:Organ of Corti / Q000473:pathology*; D011984:Sensory Receptor Cells / Q000473:pathology