The short version
- Female mice missing one metabolism gene lost high-pitched hearing by 6 weeks of age.
- Males missing the same gene kept normal hearing at 12 weeks, and lost fewer of the ear’s outer hair cells.
- The difference tracked estrogen-responsive genes in the inner ear, a clue for why hearing loss can differ between the sexes.
Bohua Hu’s lab at the University of Texas at Dallas bred mice without Slc16a5, the gene for Mct6, a protein that moves energy-related molecules in and out of cells. Female knockout mice lost high-frequency hearing by 6 weeks of age. Males did the opposite for a while: at 12 weeks they heard as well as normal mice, and they lost fewer outer hair cells, the cochlea’s sound amplifiers. The paper appeared online in June in Hearing Research; the university described it on October 14.
Gene readouts from the inner ear showed both sexes mounting the same first stress response, but the knockout shifted estrogen-responsive genes and the later steps differed by sex. The university’s account adds that the males were more vulnerable to noise injury in mid-life. “Males and females have different levels of mitochondrial energy production in ear cells,” it quotes Hu. Next, the NIH-funded team plans to look at sex-hormone receptors and cellular energy production.
This is a mouse study, and the abstract does not give group sizes. What it offers is one candidate mechanism for the gender gap in hearing loss that the lab set out to explain, still to be tested in people.
