Fan Dongyan, Ren Hailong, Danzeng Dunzhu, Li Haonan, Wang Ping
Department of Preventive Medicine, School of Medicine, Tibet University, Lhasa, Tibet 850002, P.R. China.
Department of Otolaryngology-Head and Neck Surgery, First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China.
Biomed Rep. 2016 Dec;5(6):681-685. doi: 10.3892/br.2016.791. Epub 2016 Oct 25.
The aim of the present study was to observe the histological changes in the peripheral auditory system in rats at different time-points after relocating from low altitude to high altitude (3,600 m). The general physical condition of the rats was observed and cochlear tissue samples were obtained every month. The morphology and survival of the cochlear hair cells (HCs) were observed using cochlear surface preparation at 1, 30, 90, 120, 150 and 180 days after moving to the plateau area. Changes in spiral ganglion neurons (SGNs) were detected at different time-points using immunofluorescence technology on frozen sections. No obvious morphological changes were observed in the cochlear HCs within 1-3 months of the rats moving to the plateau area, and there was little loss of outer HCs (OHCs) at 3 months. Cell swelling, dislocation and loss of cochlear OHCs were apparent at 4 months, and the losses of cochlear OHCs and inner HCs (IHCs) were 54 and 39%, respectively at 6 months. The loss of SGNs was observed at 3 months, and there was a loss of 28-35% of SGNs during 3-6 months. Thus, a high-altitude hypoxic environment influenced the cochlear HCs in rats after moving to the plateau area in a time-dependent manner. The damage to SGNs occurred earlier than the HCs, although SGN damage was not aggravated with time. Furthermore, compared with cochlear HCs, cochlear SGNs were identified to be markedly more sensitive to hypoxia, and exerted an adaptive mechanism to protect neurons from hypoxia.
本研究的目的是观察大鼠从低海拔地区迁移至高海拔地区（3600米）后不同时间点外周听觉系统的组织学变化。观察大鼠的一般身体状况，并每月获取耳蜗组织样本。在迁移至高原地区后的第1、30、90、120、150和180天，使用耳蜗表面铺片观察耳蜗毛细胞（HCs）的形态和存活情况。在不同时间点，使用免疫荧光技术在冰冻切片上检测螺旋神经节神经元（SGNs）的变化。大鼠迁移至高原地区后的1至3个月内，耳蜗HCs未观察到明显的形态变化，3个月时外毛细胞（OHCs）几乎没有损失。4个月时，耳蜗OHCs出现细胞肿胀、移位和损失，6个月时耳蜗OHCs和内毛细胞（IHCs）的损失分别为54%和39%。3个月时观察到SGNs的损失，在3至6个月期间SGNs损失了28%至35%。因此，高原低氧环境以时间依赖的方式影响大鼠迁移至高原地区后的耳蜗HCs。SGNs的损伤比HCs更早发生，尽管SGN损伤并未随时间加重。此外，与耳蜗HCs相比，耳蜗SGNs被确定对缺氧明显更敏感，并发挥了一种适应性机制来保护神经元免受缺氧影响。
