Morell Maria, Rojas Laura, Haulena Martin, Busse Björn, Siebert Ursula, Shadwick Robert E, Raverty Stephen A
Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761 Büsum, Germany.
Zoology Department, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Animals (Basel). 2022 Jan 12;12(2):180. doi: 10.3390/ani12020180.
Congenital hearing loss is recognized in humans and other terrestrial species. However, there is a lack of information on its prevalence or pathophysiology in pinnipeds. It is important to have baseline knowledge on marine mammal malformations in the inner ear, to differentiate between congenital and acquired abnormalities, which may be caused by infectious pathogens, age, or anthropogenic interactions, such as noise exposure. Ultrastructural evaluation of the cochlea of a neonate harbor seal () by scanning electron microscopy revealed bilateral loss of inner hair cells with intact outer hair cells. The selective inner hair cell loss was more severe in the basal turn, where high-frequency sounds are encoded. The loss of inner hair cells started around 40% away from the apex or tip of the spiral, reaching a maximum loss of 84.6% of hair cells at 80-85% of the length from the apex. Potential etiologies and consequences are discussed. This is believed to be the first case report of selective inner hair cell loss in a marine mammal neonate, likely congenital.
先天性听力损失在人类和其他陆生物种中已得到确认。然而，关于其在鳍足类动物中的患病率或病理生理学的信息却很匮乏。了解内耳海洋哺乳动物畸形的基线知识很重要，以便区分先天性和后天性异常，后者可能由传染性病原体、年龄或人为相互作用（如噪声暴露）引起。通过扫描电子显微镜对一只新生斑海豹的耳蜗进行超微结构评估，发现双侧内毛细胞缺失而外毛细胞完整。选择性内毛细胞缺失在高频声音编码的基底转更为严重。内毛细胞的缺失从距螺旋顶端或尖端约40%处开始，在距顶端长度的80 - 85%处达到毛细胞最大损失率84.6%。文中讨论了潜在的病因和后果。这被认为是首次报道海洋哺乳动物新生儿中出现选择性内毛细胞缺失的病例，可能为先天性。
