title: Noise alters guinea pig's blood-labyrinth barrier ultrastructure and permeability along with a decrease of cochlear Claudin-5 and Occludin.
abstract: BACKGROUND
  Noise exposure (NE) is a severe modern health hazard that induces hearing impairment. However, the noise-induced ultrastructural changes of blood-labyrinth barrier (BLB) and the potential involvements of tight junction proteins (TJP) remain inconclusive. We investigated the effects of NE on not only the ultrastructure of cochlea and permeability of BLB but also the expression of TJP within the guinea pig cochlea.
  
  
  RESULTS
  Male albino guinea pigs were exposed to white noise for 4 h or 2 consecutive days (115 dB sound pressure level, 6 hours per day) and the hearing impairments and light microscopic change of BLB were evaluated with auditory brainstem responses (ABR) and the cochlear sensory epithelia surface preparation, respectively. The cochlear ultrastructure and BLB permeability after NE 2d were revealed with transmission electron microscope (TEM) and lanthanum nitrate-tracing techniques, respectively. The potential alterations of TJPs Claudin-5 and Occludin were quantified with immunohistochemistry and western blot. NE induced significant hearing impairment and NE 2d contributed to significant outer hair cell (OHC) loss that is most severe in the first row of outer hair cells. Furthermore, the loosen TJ and an obvious leakage of lanthanum nitrate particles beneath the basal lamina were revealed with TEM. Moreover, a dose-dependent decrease of Claudin-5 and Occludin was observed in the cochlea after NE.
  
  
  CONCLUSIONS
  All these findings suggest that both decrease of Claudin-5 and Occludin and increased BLB permeability are involved in the pathologic process of noise-induced hearing impairment; however, the causal relationship and underlying mechanisms should be further investigated.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China. wuyongxianggary@163.com.|Department of Otorhinolaryngology, Head and Neck Surgery, NO.474 Hospital of Chinese PLA, Urumchi, Xinjiang, China. wuyongxianggary@163.com.
authors.forename: Yong-Xiang
authors.initials: YX
authors.lastname: Wu
authors.affiliation: Department of Otorhinolaryngology, The Affiliated Guangren Hospital of Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi, China. zhuzgxvip@163.com.
authors.forename: Guo-Xia
authors.initials: GX
authors.lastname: Zhu
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Fourth Military Medical University, Xi'an, Shaanxi, China. maomaolcw@163.com.
authors.forename: Xin-Qin
authors.initials: XQ
authors.lastname: Liu
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China. susannajoke@163.com.|Department of Physiology, Preclinical School of Medicine, Fourth Military Medical University, Xi'an, Shaanxi, China. susannajoke@163.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Sun
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China. zhouk@fmmu.edu.cn.
authors.forename: Ke
authors.initials: K
authors.lastname: Zhou
authors.affiliation: Central Laboratory, Preclinical School of Medicine, Fourth Military Medical University, Xi'an, Shaanxi, China. shuangw@fmmu.edu.cn.
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.affiliation: Central Laboratory, Preclinical School of Medicine, Fourth Military Medical University, Xi'an, Shaanxi, China. wangchunm@fmmu.edu.cn.
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Wang
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, NO.474 Hospital of Chinese PLA, Urumchi, Xinjiang, China. sayaway@163.com.
authors.forename: Jin-Wen
authors.initials: JW
authors.lastname: Jia
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, NO.474 Hospital of Chinese PLA, Urumchi, Xinjiang, China. songjt474ent@126.com.
authors.forename: Jian-Tao
authors.initials: JT
authors.lastname: Song
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China. lulianj@fmmu.edu.cn.
authors.forename: Lian-Jun
authors.initials: LJ
authors.lastname: Lu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002199:Capillary Permeability / Q000502:physiology*; D062507:Claudin-5 / Q000378:metabolism*; D003051:Cochlea / Q000503:physiopathology* / Q000648:ultrastructure*; D004848:Epithelium / Q000503:physiopathology; D016057:Evoked Potentials, Auditory, Brain Stem; D006168:Guinea Pigs; D006317:Hearing Loss, Noise-Induced / Q000473:pathology / Q000503:physiopathology; D007150:Immunohistochemistry; D007811:Lanthanum; D008297:Male; D046529:Microscopy, Electron, Transmission; D009622:Noise / Q000009:adverse effects*; D062793:Occludin / Q000378:metabolism*; D011897:Random Allocation
chemical_list: D062507:Claudin-5; D062793:Occludin; C016534:lanthanide nitrate; D007811:Lanthanum