title: Intra-tympanic delivery of short interfering RNA into the adult mouse cochlea.
abstract: Trans-tympanic injection into the middle ear has long been the standard for local delivery of compounds in experimental studies. Here we demonstrate the advantages of the novel method of intra-tympanic injection through the otic bone for the delivery of compounds or siRNA into the adult mouse cochlea. First, a fluorescently-conjugated scrambled siRNA probe was applied via intra-tympanic injection into the middle ear cavity and was detected in sensory hair cells and nerve fibers as early as 6 h after the injection. The fluorescent probe was also detected in other cells of the organ of Corti, the lateral wall, and in spiral ganglion cells 48 h after the injection. Furthermore, intra-tympanic delivery of Nox3 siRNA successfully reduced immunofluorescence associated with Nox3 in outer hair cells 72 h after injection by 20%. Drug or siRNA delivery via intra-tympanic injection does not compromise the tympanic membrane or interfere with noise-induced hearing loss, while trans-tympanic injections significantly altered the cochlear response to noise exposure. In summary, intra-tympanic injection through the otic bone into the middle ear cavity provides a promising approach for delivery of compounds or siRNA to cochlear hair cells of adult mice, relevant for the study of mechanisms underlying inner ear insults and, specifically, noise-induced hearing loss.
authors.affiliation: Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI 48109-5616, USA.
authors.forename: Naoki
authors.initials: N
authors.lastname: Oishi
authors.forename: Fu-Quan
authors.initials: FQ
authors.lastname: Chen
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Zheng
authors.forename: Su-Hua
authors.initials: SH
authors.lastname: Sha
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold; D003051:Cochlea / Q000378:metabolism* / Q000503:physiopathology; D004195:Disease Models, Animal; D015536:Down-Regulation; D004432:Ear, Middle; D016057:Evoked Potentials, Auditory, Brain Stem; D005455:Fluorescent Antibody Technique; D018014:Gene Transfer Techniques; D006198:Hair Cells, Auditory / Q000378:metabolism; D006317:Hearing Loss, Noise-Induced / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D007267:Injections; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D009622:Noise; D011677:Punctures; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000378:metabolism; D013136:Spiral Ganglion / Q000378:metabolism; D013997:Time Factors; D014432:Tympanic Membrane
chemical_list: D034741:RNA, Small Interfering; D019255:NADPH Oxidases; C484511:Nox3 protein, mouse