TrkB Mediated Protection Against Circadian Sensitivity to Noise Trauma in the Murine Cochlea

Highlights

•The cochlea possesses a self-sustained circadian clock

•Noise sensitivity is greater during the active phase than during the inactive phase

•The BDNF receptor TrkB modulates the auditory clock

•Activation of TrkB during the active phase prevents noise-induced hearing loss


Summary

Noise-induced hearing loss (NIHL) is a debilitating sensory impairment affecting 10%–15% of the population, caused primarily through damage to the sensory hair cells or to the auditory neurons. Once lost, these never regenerate [1], and no effective drugs are available [2, 3]. Emerging evidence points toward an important contribution of synaptic ribbons in the long-term coupling of the inner hair cell and afferent neuron synapse to maintain hearing [4]. Here we show in nocturnal mice that night noise overexposure triggers permanent hearing loss, whereas mice overexposed during the day recover to normal auditory thresholds. In view of this time-dependent sensitivity, we identified a self-sustained circadian rhythm in the isolated cochlea, as evidenced by circadian expression of clock genes and ample PERIOD2::LUCIFERASE oscillations, originating mainly from the primary auditory neurons and hair cells. The transcripts of the otoprotecting brain-derived neurotrophic factor (BDNF) showed higher levels in response to day noise versus night noise, suggesting that BDNF-mediated signaling regulates noise sensitivity throughout the day. Administration of a selective BDNF receptor, tropomyosin-related kinase type B (TrkB), in the night protected the inner hair cell’s synaptic ribbons and subsequent full recovery of hearing thresholds after night noise overexposure. The TrkB agonist shifted the phase and boosted the amplitude of circadian rhythms in the isolated cochlea. These findings highlight the coupling of circadian rhythmicity and the TrkB receptor for the successful prevention and treatment of NIHL.

http://www.cell.com/current-biology/fulltext/S0960-9822(14)00080-3

 

Woah! This is some real progress here. You still won't find me volunteering to be a NIHL test dummy.

 

Can someone please explain to me what this means for us? This research paper just went completely over my head.

 

@jer
Maybe this link help a little to enlight you.....
https://en.wikipedia.org/wiki/Circadian_rhythm

The article attached in this thread (not new / its from february 2014) remind me one of my older and wise family member who have been told me since 20 years ago that i was living too much the night (not rested enough....)
.....and she is not a researcher!
Well, it seems it was a good advise and alert to me (since 20 years ago....) that i sadly ignored....

We are a very complex natural machine!

 

http://news.cision.com/karolinska-i...for-people-with-hearing-disabilities,c9540948

 

Awesome find!!! Very interesting article!!!

 

I've worked swing shift around loud machines for the past two years and even with hearing protection my tinnitus has gotten worse. I've been trying to figure out what's up, this may be it. Now to find out if this TrkB is something I can get my hands on.