Exposure to intense noise can damage cochlear hair cells, leading to hearing loss in mammals. To avoid this constraint, most mammals have evolved in relatively quiet environments. Echolocating bats, however, are naturally exposed to continuous intense sounds from their own and neighboring sonar emissions for maintaining sonar directionality and range. Here, we propose the presence of intense noise resistance in cochlear hair cells of echolocating bats against noise-induced hearing loss (NIHL). To test this hypothesis, we performed noise exposure experiments for laboratory mice, one nonecholocating bat species, and five echolocating bat species. Contrary to nonecholocating fruit bats and mice, the hearing and the cochlear hair cells of echolocating bats remained unimpaired after continuous intense noise exposure. The comparative analyses of cochleae transcriptomic data showed that several genes protecting cochlear hair cells from intense sounds were overexpressed in echolocating bats. Particularly, the experimental examinations revealed that ISL1 overexpression significantly improved the survival of cochlear hair cells. Our findings support the existence of protective effects in cochlear hair cells of echolocating bats against intense noises, which provides new insight into understanding the relationship between cochlear hair cells and intense noises, and preventing or ameliorating NIHL in mammals.

暴露在强烈的噪音中会损害耳蜗毛细胞，导致哺乳动物听力下降。为了避免这种限制，大多数哺乳动物都在相对安静的环境中进化。然而，回声定位的蝙蝠会自然地暴露在来自其自身和邻近声纳发射的持续强烈声音中，以保持声纳的方向性和范围。在这里，我们提出在回声定位蝙蝠的耳蜗毛细胞中存在强烈的抗噪声性，以对抗噪声引起的听力损失 (NIHL)。为了验证这一假设，我们对实验室小鼠、一种非回声定位蝙蝠和五种回声定位蝙蝠进行了噪声暴露实验。与非回声定位的果蝠和小鼠相反，回声定位蝙蝠的听力和耳蜗毛细胞在持续强烈的噪音暴露后仍然完好无损。耳蜗转录组数据的比较分析表明，保护耳蜗毛细胞免受强烈声音影响的几个基因在回声定位蝙蝠中过度表达。特别是，实验检查表明，ISL1过表达显着提高了耳蜗毛细胞的存活率。我们的研究结果支持回声定位蝙蝠的耳蜗毛细胞对强噪声存在保护作用，这为理解耳蜗毛细胞与强噪声之间的关系以及预防或改善哺乳动物的 NIHL 提供了新的见解。