A new method for three-dimensional immunofluorescence study of the cochlea

• Published in: Hearing research Vol. 392; p. 107956
• Main Authors: Brody, Kate M., Hampson, Amy J., Cho, Hyun-jung, Johnson, Prudence, O’Leary, Stephen J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2020
• Subjects: Cochlear implant; Immunofluorescence; Light sheet microscopy; Tissue clearing; Whole cochlea imaging; Tissue clearing; Cochlear implant; Light sheet microscopy; Immunofluorescence; Whole cochlea imaging
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/j.heares.2020.107956

Visualisation of cochlear histopathology in three-dimensions has been long desired in the field of hearing research. This paper outlines a technique that has made this possible and shows a research application in the field of hearing protection after cochlear implantation. The technique utilises robust immunofluorescent labelling followed by effective tissue clearing and fast image acquisition using Light Sheet Microscopy. We can access the health of individual components by immunofluorescent detection of proteins such as myosin VIIa to look at cochlear hair cells, NaKATPase alpha 3 to look at spiral ganglion neurons, and IBA1 to look at macrophages within a single cochlea, whilst maintaining the integrity of fine membranous structures and keeping the cochlear implant in place. This allows the tissue response to cochlear implantation to be studied in detail, including the immune reaction to the implant and the impact on the structure and health of neural components such as hair cells. This technique reduces time and labour required for sectioning of cochleae and can allow visualisation of cellular detail. Use of image analysis software allows conversion of high-resolution image stacks into three-dimensional interactive data sets so volumes and numbers of surfaces can be measured. Immunofluorescent whole cochlea labelling and Light Sheet Microscopy have the capacity to be applied to many questions in hearing research of both the cochlea and vestibular system. •A new method for three-dimensional immunofluorescence study of the cochlea.•A method enabling 3D immunofluorescence study of the whole cochlea has been developed.•Complete 3D visualisation of multiple cochlear components can be achieved in a single cochlea, without affecting tissue structure or integrity.•Whole cochleae can be imaged in detail with a cochlear implant electrode in situ.