Related Experiment Video
Updated: Dec 13, 2025
A Protocol for Decellularizing Mouse Cochleae for Inner Ear Tissue Engineering
Published on: January 1, 2018
Three-Dimensional Distribution of Cochlear Macrophages in the Lateral Wall of Cleared Cochlea
Seong Hoon Bae1, Sang Hyun Kwak1, Jee Eun Yoo1
1Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea.
Objectives:
Resident macrophages are well known to be present in the cochlea, but the exact patterns thereof in spiral ligaments have not been discussed in previous studies. We sought to document the distribution of macrophages in intact cochleae using three-dimensional imaging.
Methods:
Cochleae were obtained from C-X3-C motif chemokine receptor 1+/GFP mice, and organ clearing was performed. Three-dimensional images of cleared intact cochleae were reconstructed using two-photon microscopy. The locations of individual macrophages were investigated using 100-μm stacked images to reduce bias. Cochlear inflammation was then induced by lipopolysaccharide (LPS) inoculation into the middle ear through the tympanic membrane. Four days after inoculation, three-dimensional images were obtained.
Results:
Macrophages were scarce in areas adjacent to the stria vascularis, particularly the area just beneath it even though many have suspected macrophages to be abundant in this area. This finding remained consistent upon LPS-induced cochlear inflammation, despite a significant increase in the number of macrophages, compared to non-treated cochlea.
Conclusion:
Resident macrophages in spiral ligaments are scarce in areas adjacent to the stria vascularis.
Insights
Resident macrophages are scarce in the cochlea near the stria vascularis. This distribution pattern persists even after induced cochlear inflammation, challenging previous assumptions.
Area of Science:
- Otolaryngology
- Immunology
- Cell Biology
Background:
- Resident macrophages are known to inhabit the cochlea.
- Their precise distribution within the spiral ligaments remains underexplored.
Purpose of the Study:
- To map the distribution of macrophages in intact cochleae using 3D imaging.
- To investigate macrophage patterns in spiral ligaments, particularly near the stria vascularis.
Main Methods:
- Utilized C-X3-C motif chemokine receptor 1+/GFP mice for cochlear imaging.
- Employed organ clearing and two-photon microscopy for 3D reconstruction.
- Induced cochlear inflammation with lipopolysaccharide (LPS) to assess macrophage response.
Main Results:
- Macrophages were found to be scarce in areas adjacent to the stria vascularis.
- This scarcity was observed despite the suspected abundance of macrophages in this region.
- LPS-induced inflammation significantly increased macrophage numbers but did not alter the scarcity near the stria vascularis.
Conclusions:
- Resident macrophages in the spiral ligaments are notably scarce in regions adjacent to the stria vascularis.
- The distribution pattern is consistent even under inflammatory conditions.
