School of Neurobiology, Biochemistry, and Biophysics, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
Life Sci Alliance. 2023 Mar 30;6(6). doi: 10.26508/lsa.202201847. Print 2023 Jun.
Hearing loss is a hallmark of aging, typically initially affecting the higher frequencies. In echolocating bats, the ability to discern high frequencies is essential. However, nothing is known about age-related hearing loss in bats, and they are often assumed to be immune to it. We tested the hearing of 47 wild Egyptian fruit bats by recording their auditory brainstem response and cochlear microphonics, and we also assessed the cochlear histology in four of these bats. We used the bats' DNA methylation profile to evaluate their age and found that bats exhibit age-related hearing loss, with more prominent deterioration at the higher frequencies. The rate of the deterioration was ∼1 dB per year, comparable to the hearing loss observed in humans. Assessing the noise in the fruit bat roost revealed that these bats are exposed to continuous immense noise-mostly of social vocalizations-supporting the assumption that bats might be partially resistant to loud noise. Thus, in contrast to previous assumptions, our results suggest that bats constitute a model animal for the study of age-related hearing loss.
听力损失是衰老的一个标志，通常最初影响高频。在回声定位蝙蝠中，辨别高频的能力至关重要。然而，关于蝙蝠的与年龄相关的听力损失知之甚少，通常认为它们对此具有免疫力。我们通过记录听觉脑干反应和耳蜗微音器来测试 47 只野生埃及果蝠的听力，还评估了其中 4 只蝙蝠的耳蜗组织学。我们使用蝙蝠的 DNA 甲基化特征来评估它们的年龄，发现蝙蝠表现出与年龄相关的听力损失，高频的恶化更为明显。恶化的速度约为每年 1 分贝，与人类观察到的听力损失相当。对果蝠栖息地的噪声评估表明，这些蝙蝠长期暴露在持续的巨大噪声中，主要是社交叫声，这支持了蝙蝠可能对大声噪声有一定抵抗力的假设。因此，与之前的假设相反，我们的结果表明，蝙蝠是研究与年龄相关的听力损失的模型动物。
