@article {Yoshida10116, author = {Naohiro Yoshida and Arthur Kristiansen and M. Charles Liberman}, title = {Heat Stress and Protection from Permanent Acoustic Injury in Mice}, volume = {19}, number = {22}, pages = {10116--10124}, year = {1999}, doi = {10.1523/JNEUROSCI.19-22-10116.1999}, publisher = {Society for Neuroscience}, abstract = {The inner ear can be permanently damaged by overexposure to high-level noise; however, damage can be decreased by previous exposure to moderate level, nontraumatic noise (Canlon et al., 1988). The mechanism of this {\textquotedblleft}protective{\textquotedblright} effect is unclear, but a role for heat shock proteins has been suggested. The aim of the present study was to directly test protective effects of heat stress in the ear. For physiological experiments, CBA/CaJ mice were exposed to an intense octave band of noise (8{\textendash}16 kHz) at 100 dB SPL for 2 hr, either with or without previous whole-body heat stress (rectal temperature to 41.5 {\textdegree}C for 15 min). The interval between heat stress and sound exposure varied in different groups from 6 to 96 hr. One week later, inner ear function was assessed in each animal via comparison of compound action potential thresholds to mean values from unexposed controls. Permanent threshold shifts (PTSs) were \~{}40 dB in the group sound-exposed without previous heat stress. Heat-stressed animals were protected from acoustic injury: mean PTS in the group with 6 hr heat-stress{\textendash}trauma interval was reduced to \~{}10 dB. This heat stress protection disappeared when the treatment-trauma interval surpassed 24 hr. A parallel set of quantitative PCR experiments measured heat-shock protein mRNA in the cochlea and showed 100- to 200-fold increase over control 30 min after heat treatment, with levels returning to baseline at 6 hr after treatment. Results are consistent with the idea that upregulation of heat shock proteins protects the ear from acoustic injury.}, issn = {0270-6474}, URL = {https://www.jneurosci.org/content/19/22/10116}, eprint = {https://www.jneurosci.org/content/19/22/10116.full.pdf}, journal = {Journal of Neuroscience} }