Gene Expression Changes in Chinchilla Cochlea from Noise-Induced Temporary Threshold Shift.

Area of Science:

• Otoacoustic emissions
• Inner ear physiology
• Molecular biology

Background:

• Acoustic overstimulation causes inner ear changes, but underlying gene expression alterations are unclear.
• Noise exposure can lead to temporary threshold shifts and reduced otoacoustic emissions without permanent damage.

Purpose of the Study:

• To investigate noise-induced gene expression changes in the chinchilla inner ear.
• To assess the suitability of mouse and human cDNA clones for chinchilla gene transcript detection.

Main Methods:

• Utilized gene microarrays to measure gene expression changes in chinchilla cochlea after 3h and 6h noise exposure (95 dB SPL).
• Employed mouse cDNA microarrays with differentially labeled chinchilla cDNA probes (Cy3/Cy5) for hybridization and laser fluorescent microscopy analysis.
• Validated mouse and human cDNA clones for detecting chinchilla cochlear gene transcripts.

Main Results:

• Chinchilla cochlear transcript probes showed strong signals on mouse and human cDNA arrays, with superior hybridization to mouse clones.
• Several gene classes, including those for protein synthesis, metabolism, cytoskeletal proteins, and calcium binding proteins, showed time-dependent upregulation.
• Noise exposure induced temporary threshold shifts and reduced distortion product otoacoustic emissions (DPOAEs).

Conclusions:

• Mouse cDNA microarrays are suitable for studying noise-induced gene expression in chinchillas.
• Noise exposure triggers significant, time-dependent changes in cochlear gene expression, particularly in genes related to cellular function and structure.
• Findings align with previous research on noise-induced alterations in structural proteins, calcium binding proteins, and metabolic enzymes.