Growth hormone helps repair the zebrafish ear

September 2, 2011

Loud noise, especially repeated loud noise, is known to cause irreversible damage to the hair cells inside the cochlea and eventually lead to deafness. In mammals this is irreversible, however both birds and fish are able to re-grow the damaged hair cells and restore hearing. New research published in BioMed Central's open access journal BMC Neuroscience shows that growth hormone is involved in this regeneration in zebrafish.

Researchers from Western Kentucky University and the University of Louisville worked together to see which genes were switched on or off after and found distinct patterns of gene expression. Two days after noise injury, cells were busy dividing to repair and replace the damaged hair cells. This repair was associated with an alteration in the regulation of 839 genes and many of the involved were the same as those involved in cancer. This included a massive 64 fold increase in the transcription of growth hormone.

MHC I ZE (a gene involved in regulating immune responses) is down-regulated. But, since a strong inflammatory response to tissue damage can interfere with wound healing, it is probably a good idea to locally inhibit the immune response while repairing injury. Four days after trauma, these levels had begun to return to normal.

Dr. Michael Smith commented, "Injecting growth hormone into zebrafish stimulated cell proliferation in their inner ears, especially cells of the utricle, a vestibular organ involved in balance. There are many homologs between zebrafish and and we are beginning to work on the function of these genes within the ear. Understanding how fish are able to repair their may eventually help us to understand ear injury in people and provide treatments for hair cell loss."

Related Stories

Recommended for you

New mechanism discovered behind infant epilepsy

September 3, 2015

Scientists at Karolinska Institutet and Karolinska University Hospital in Sweden have discovered a new explanation for severe early infant epilepsy. Mutations in the gene encoding the protein KCC2 can cause the disease, hereby ...

Neuron responsible for alcoholism found

September 2, 2015

Scientists have pinpointed a population of neurons in the brain that influences whether one drink leads to two, which could ultimately lead to a cure for alcoholism and other addictions.

Deciphering the olfactory receptor code

August 31, 2015

In animals, numerous behaviors are governed by the olfactory perception of their surrounding world. Whether originating in the nose of a mammal or the antennas of an insect, perception results from the combined activation ...

Scientists see motor neurons 'walking' in real time

September 2, 2015

When you're taking a walk around the block, your body is mostly on autopilot—you don't have to consciously think about alternating which leg you step with or which muscles it takes to lift a foot and put it back down. That's ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.