Brevican immunoreactivity in the mouse cochlea during development and following noise-induced hearing loss

Perineuronal nets (PNNs) regulate synaptic stabilization and neural circuit development in the central nervous system. Although BCAN-associated extracellular matrix specializations have been described in the cochlea, their developmental organization and response to acoustic injury remain poorly understood. Here we characterized BCAN-associated extracellular matrix in the developing and adult mouse cochlea and examined changes following noise-induced hearing loss (NIHL).

HAPLN1 and neurocan were broadly detected around inner hair cells from postnatal day 7 (P7), whereas BCAN immunoreactivity was not detected at P7 but was detectable around the inner hair cell (IhC) region at P14. RNA in situ hybridization and exploratory analysis of published single-cell transcriptomic datasets characterized developmental patterns of BCAN mRNA signals in spiral ganglion-associated cell populations. Three-dimensional cochlear clearing and light-sheet imaging qualitatively revealed BCAN immunoreactivity surrounding a subset of cell bodies in the auditory nerve transitional region of adult cochleae.

Following permanent-threshold-shift–inducing noise exposure, BCAN immunoreactivity was markedly reduced in the IhC region and appeared less prominent around cell bodies in the auditory nerve transitional region. These findings further characterize BCAN-associated extracellular matrix patterns in the mouse cochlea and describe developmental changes in BCAN immunoreactivity and its reduction following severe NIHL. This work was supported by the fund from Seoul National University (800-20250270), Creative-Pioneering Researchers Program through Seoul National University (800-20250440), the research grant (RS-2025-25459502) from the Korea Health Industry Development Institute (KHIDI), and the research grant (RS-2026-25490236) from the National Research Foundation (NRF) of Korea.

Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea Department of Otorhinolaryngology, Boramae Medical Center, Seoul Metropolitan Government-Seoul National University, Seoul, 07061, Republic of Korea Department of Otorhinolaryngology, College of Medicine, Seoul National University, 103, Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea The authors declare no competing interests. The NRF had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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