PEOPLE’S ability to hear depends on bundles of tiny hairs found inside their ears. When these bundles vibrate in response to sound, cells at their base send signals to the brain, which then translates them into the rich symphony that fills the world. In normal circumstances, this symphony leaves the hairs unharmed. But exceptionally loud noises—close cracks of thunder, the emissions of rock-concert loudspeakers and so on—can disorganise the bundles, traumatising and sometimes killing the cells they are connected to. Doctors have long believed such damage to be irreversible, but an experiment led by Glen Watson of the University of Louisiana, Lafayette, and published in the Journal of Experimental Biology, suggests an ointment containing proteins harvested from sea anemones may do the trick.

Some anemones, such as Nematostella vectensis, pictured above, have a primitive sense of hearing: tiny hair bundles scattered along their tentacles sense when animals that they can sting are nearby. Wounds from battles with struggling prey often disorganise these bundles but, unlike the hair bundles found in the ears of mammals, anemone bundles mend themselves in the space of four hours.

During previous work, Dr Watson noticed that a mixture of 37 proteins from Nematostella, including several known to help either repair or destroy misfolded proteins, were used by the anemones to reorganise their dishevelled bundles. He therefore wondered whether these could repair other animals’ hair bundles, too. To find out, he isolated the anemone protein mixture and applied it to damaged sensory hair bundles from blind cavefish. He knew from another study on these fish that their hair bundles usually took nine days to recover after being damaged. Applying the anemone proteins reduced the recovery period to a little over an hour. This led him to try the same thing with mammals.

He and his colleagues removed the organs of Corti, home of the hair bundles, from the ears of mouse pups, and cultured them on microscope-slide cover slips. Once the team were sure the cultures were stable, they exposed them for 15 minutes to one of two solutions. The first contained healthy levels of calcium. The second was calcium-free, a fact they knew would cause the bundles to lose their structure. They then incubated the slips in another sort of solution—in this case either enriched in anemone repair proteins, or not. After an hour of this, they stained the samples and studied them under a microscope.

To quantify matters, they examined transects 50 microns long from each sample. Such transects would traverse six bundles in a healthy animal. They assigned a score of 1.0 to bundles that were clearly healthy and well organised, a score of 0.5 to those that were disorganised but present, and a score of zero to sites where hairs should have been but weren’t. Scored this way, transects from healthy controls averaged 5.9 while those from untreated traumatised tissue averaged 2.2. Traumatised tissue that had been treated subsequently with the anemone-repair-protein solution, though, had an average score of 5.1. It had indeed been repaired.

While repairing hair bundles in samples of mouse-pup ear tissue is not the same thing as repairing those inside the ears of people suffering from hearing loss, Dr Watson’s findings suggest that a treatment of this sort may be possible in the not too distant future. If he is right, those who regret that front seat at Madison Square Garden in their misspent youths may have a chance to redeem themselves.