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  • [INTRO ♫]

  • Everywhere from construction jobs to rock concerts,

  • loud noise carries a risk of permanent damage to your hearing.

  • But a new study published this week in the journal PNAS

  • has found a chemical trick that might help block

  • the harmful effects of noise on our ears.

  • They developed a drug-based procedure

  • that actually prevented hearing loss in mice.

  • The secret is targeting a key stage in the journey

  • of audio information from the ear to the brain.

  • So sound is picked up by hair cells in our ears,

  • then delivered to nerve cells, which carry the information to our brains.

  • This drug works at the junction -- or synapse --

  • between the hair cells and nerve cells.

  • When a hair cell picks up a sound, it releases a chemical

  • called glutamate, which is then received by special receptors

  • on the surface of nerve cells.

  • But if the sound is very loud or sustained for a long time,

  • the hair cells can produce too much of a good thing.

  • In those cases, a deluge of glutamate is transmitted,

  • and this overexposure can cause damage at the junction

  • between hair cells and nerve cells.

  • That damage is known as synaptopathy,

  • and it's one common type of hearing loss.

  • Previous research has found that this damage might be

  • related to the flow of ions, especially calcium.

  • Excess calcium has been implicated in helping along

  • the toxicity that results from too much glutamate signaling.

  • But not all of these receptors actually let much calcium in.

  • It comes down to whether or not they have a protein called GluA2.

  • Each glutamate receptor is made up of a handful of proteins.

  • GluA2 is one of these, but not all receptors have it.

  • It seems that receptors without GluA2 are much more permeable

  • to calcium flow, and that makes them vulnerable to

  • the harmful chemical effects of loud noises.

  • For the time being, we don't have any way of repairing

  • this noise-induced damage.

  • It means permanent hearing loss.

  • So these researchers wondered if they could instead

  • stop it from happening in the first place.

  • So they surgically introduced a drug called IEM-1460

  • into the inner ears of mice.

  • The drug blocked the function of

  • the nerve receptors lacking GluA2.

  • The result was no damage to synapses,

  • and no hearing loss in the mice.

  • The technique has been referred to aschemical earmuffs,”

  • but since the drug only blocks some of the sound receptors in the ear,

  • the mice's brains still responded to sound normally,

  • suggesting they could still hear just fine.

  • If this idea can be adapted for humans, it has a ton of potential

  • for preventing hearing damage.

  • Imagine being able to take a pill before going to a concert --

  • all of the rock, none of the hearing loss.

  • Or before going to a job like construction or manufacturing,

  • where hearing loss can be a daily risk.

  • But remember -- this was only in mice,

  • and the researchers had to inject the drug directly

  • into their inner ears.

  • It's got a long way to go before it's ready for use in people.

  • But while those scientists are hoping to help people

  • keep their hearing, another group in Antarctica

  • has been seeing things no one's ever seen before.

  • They've developed and deployed an underwater robot

  • to take a peek underneath a glacier.

  • It's known as Thwaites glacier.

  • It covers an area about the size of the state of Florida,

  • and its melting accounts for about 4% of global sea level rise.

  • Most of the glacier is part of Antarctica's continental ice,

  • but at its end, it flows out to sea and gives rise

  • to a floating ice shelf.

  • The amount of ice flowing through this region of Antarctica

  • has nearly doubled in the last 30 years.

  • It's one of the most rapidly changing regions

  • of the frozen continent, and this has a huge impact

  • on our oceans.

  • All this makes Thwaites kind of a big deal for scientists

  • seeking to understand our changing climate.

  • In particular, this team of scientists, part of the

  • International Thwaites Glacier Collaboration, wanted to get a look

  • underneath the glacier, at an area called the grounding zone.

  • The grounding zone is the area where the glacier transitions

  • from sitting on land to floating on water.

  • It's also a prime region of glacial change,

  • where the ice can be eroded away by warming ocean waters.

  • So understanding what's going on in the grounding zone

  • can give us a lot of information about the future

  • of this very important hunk of ice

  • and its impact on our seas.

  • But the grounding zone is a treacherous,

  • hard-to-reach place, so the team made a robot

  • to venture where they could not.

  • It's called Icefin.

  • It's a submersible robot designed to collect data

  • in the grounding zone.

  • From atop the glacier, the team drilled roughly 700 meters down

  • to the seawater below and lowered Icefin through.

  • Once it was down there, the robot took a trip

  • of over a kilometer to measure, image, and map the grounding zone.

  • The success of Icefin opens up a whole new way for researchers

  • to measure and monitor rapidly-changing glaciers like Thwaites.

  • Another Icefin robot has already been deployed under

  • the Kamb Ice Stream, a river of ice on Antarctica's Ross Ice Shelf.

  • As our world continues to change in dramatic ways,

  • science like this will help us keep an eye

  • on the most vulnerable parts of the globe.

  • Thanks for watching this episode of SciShow,

  • which is produced by Complexly.

  • If you want to keep imagining the world complexly with us,

  • check out our channel Animal Wonders

  • hosted by Jessi Knudsen Castañeda.

  • Animal Wonders is an animal rescue and education facility

  • that cares for close to 100 exotic animals and non-releasable wildlife.

  • They're an educational outreach facility based here in Montana,

  • and they rescue displaced exotic animals

  • and allow them to become ambassadors for their species.

  • Every week on the Animal Wonders YouTube channel,

  • Jessi features different animals and shares what it's like

  • to keep them happy and healthy.

  • Recently, Jessi and the Animal Wonders team took in Tigli the arctic fox.

  • If you'd like to learn all about Tigli's story and find out

  • how he's getting along with the other foxes at Animal Wonders,

  • there is a link in the description to a video all about that.

  • [OUTRO ♫]

[INTRO ♫]

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化學耳罩。聽力保護的未來?| 科學秀新聞 (Chemical Earmuffs: The Future of Hearing Protection? | SciShow News)

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    林宜悉 發佈於 2021 年 01 月 14 日
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