Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea.
Department of Otorhinolaryngology, Myongji Hospital, Hanyang University College of Medicine, Goyang, South Korea.
Sci Rep. 2018 Nov 6;8(1):16415. doi: 10.1038/s41598-018-34653-8.
Vitamin A deficiency (VAD) produces various pathologic phenotypes in humans and animals. However, evidence regarding the effect of VAD on hearing function has been inconsistent. In this study, we evaluated the effect of VAD on hearing function in two mouse models of VAD. Hearing ability was evaluated on the basis of auditory brainstem response from 3 to 20 weeks after birth in C57BL/6 (pigmented) and imprinting control region (albino) mice. The two mice strains were divided into the VAD (purified vitamin A-free diet from 7 days after pregnancy) and control (normal diet) groups. Albino VAD mice exhibited hearing loss after 6 weeks and became deaf at 18 weeks. Histological findings revealed degenerative changes in outer hair cells and neuronal loss in the spiral ganglion in albino VAD mice. In contrast, pigmented VAD mice, except those with middle-ear infection, showed no significant hearing loss. Interestingly, pigmented VAD mice exhibited melanocyte activation in the stria vascularis and upregulation of tyrosinase. Recovery of hearing after noise exposure was poorer in pigmented VAD mice than in control mice. In conclusion, complete VAD might be related to age-related or noise-induced hearing loss in mice, protection against which might involve melanocyte activation.
维生素 A 缺乏症 (VAD) 可导致人类和动物出现多种病理表型。然而，关于 VAD 对听力功能影响的证据一直存在不一致。在这项研究中，我们在两种 VAD 小鼠模型中评估了 VAD 对听力功能的影响。在出生后 3 至 20 周，通过听觉脑干反应评估 C57BL/6（色素沉着）和印记控制区（白化）小鼠的听力能力。将这两种小鼠分为 VAD（妊娠后 7 天开始使用纯化的不含维生素 A 的饮食）和对照（正常饮食）组。白化 VAD 小鼠在 6 周后出现听力损失，18 周后失聪。组织学发现白化 VAD 小鼠的外毛细胞变性和螺旋神经节神经元丢失。相比之下，除中耳感染外，色素沉着 VAD 小鼠没有明显的听力损失。有趣的是，色素沉着 VAD 小鼠的血管纹中的黑素细胞激活和酪氨酸酶的上调。与对照组相比，噪声暴露后色素沉着 VAD 小鼠的听力恢复较差。总之，完全的 VAD 可能与小鼠的年龄相关性或噪声诱导性听力损失有关，而黑素细胞的激活可能对其有保护作用。
