Related Experiment Video
Updated: Aug 13, 2026
07:13
Modified Experimental Conditions for Noise-Induced Hearing Loss in Mice and Assessment of Hearing Function and Outer Hair Cell Damage
Published on: February 10, 2023
Proinflammatory cytokines expression in noise-induced damaged cochlea
Masato Fujioka1, Sho Kanzaki, Hirotaka James Okano
1Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, Tokyo, Japan.
Journal of Neuroscience Research
|January 24, 2006
Summary
Noise exposure triggers inflammatory responses in the inner ear. Proinflammatory cytokines like interleukin-6 (IL-6) are rapidly produced in the cochlea, potentially contributing to noise-induced hearing damage.
Area of Science:
- Oto-neurology
- Immunology
- Cell Biology
Background:
- Inflammatory responses are implicated in inner ear damage from various stimuli, including noise.
- Understanding the early molecular events following noise overstimulation is crucial for developing protective strategies.
Purpose of the Study:
- To investigate the time-dependent expression of proinflammatory cytokines in the rat cochlea after noise exposure.
- To identify the specific cell types and locations of cytokine production in response to acoustic trauma.
Main Methods:
- Real-time RT-PCR was used to quantify cytokine mRNA levels (IL-1beta, IL-6, TNF-alpha).
- Immunohistochemistry was employed to localize cytokine protein expression (IL-6) within cochlear structures.
- Iba-1 staining was performed to assess macrophage/microglia activation.
Main Results:
- Interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) showed significant induction 3 hours post-noise exposure, followed by rapid downregulation.
- Tumor necrosis factor-alpha (TNF-alpha) exhibited transient upregulation immediately after noise exposure.
- IL-6 expression was localized to the spiral ligament, stria vascularis, and spiral ganglion neurons, not initially involving immune cell activation.
Conclusions:
- The cochlea itself produces key proinflammatory cytokines (TNF-alpha, IL-1beta, IL-6) in the early phase of noise overstimulation.
- IL-6 expression in specific cochlear cells suggests a role in initiating inflammatory responses and noise-induced cochlear damage.
Related Concept Videos
01:28Inflammatory Response
An inflammatory response is a localized, nonspecific immune reaction that occurs when a tissue is injured. It is characterized by redness, swelling, heat, and pain, which are commonly called the cardinal signs and symptoms of inflammation. Inflammation can sometimes result in a loss of function.
Inflammation can be triggered by various stimuli, such as impact, abrasion, chemical irritation, infections, and extreme hot or cold temperatures. These can damage cells and connective tissue fibers,...
Inflammation can be triggered by various stimuli, such as impact, abrasion, chemical irritation, infections, and extreme hot or cold temperatures. These can damage cells and connective tissue fibers,...
01:13The Cochlea
The cochlea is a coiled structure in the inner ear that contains hair cells—the sensory receptors of the auditory system. Sound waves are transmitted to the cochlea by small bones attached to the eardrum called the ossicles, which vibrate the oval window that leads to the inner ear. This causes fluid in the chambers of the cochlea to move, vibrating the basilar membrane.