title: Cochlear damages caused by vibration exposure.
abstract: BACKGROUND
  Many industrial devices have an excessive vibration which can affect human body systems. The effect of vibration on cochlear histology has been as a debatable problem in occupational health and medicine.
  
  
  OBJECTIVE
  Due to limitation present in human studies, the research was conducted to survey the influence of vibration on cochlear histology in an animal model.
  
  
  METHODS
  TWELVE ALBINO RABBITS WERE EXPERIMENTED AS: Vibration group (n = 6; exposed to 1.0 m.s(-2) r.m.s vertical whole-body vibration at 4 - 8 Hz for 8 hours per day during 5 consecutive days) versus Control group (n = 6; the same rabbits without vibration exposure). After finishing the exposure scenario, all rabbits were killed by CO2 inhalation; their cochleae were extracted and fixed in 10% formaldehyde for 48 hours, decalcified by 10% nitric acid for 24 hours. Specimens were dehydrated, embedded, sectioned 5 µm thick and stained with Hematoxylin and Eosin for light microscopy observations.
  
  
  RESULTS
  Severely hydropic degenerated and vacuolated inner hair cells (IHCs) were observed in vibration group compared to the control group. Inter and intracellular edema was appeared in supporting cells (SC). Nuclei of outer hair cells (OHCs) seemed to be pyknotic. Slightly thickened basilar membrane (BM) was probably implied to inter cellular edematous. Tectorial Membrane (TM) was not affected pathologically.
  
  
  CONCLUSIONS
  Whole-body vibration could cause cochlear damages in male rabbits, though vibration-induced auditory functional effects might be resulted as subsequent outcome of prolonged high level vibration exposures.
authors.affiliation: Department of Occupational Hygiene, Collage of Health, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Seyyed Ali
authors.initials: SA
authors.lastname: Moussavi Najarkola
authors.affiliation: Department of Occupational Health, School of Medical Sciences, Tarbiat Modares University, Tehran, IR Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Khavanin
authors.affiliation: Department of Occupational Health, Health Promotion Research Center, Zahedan University of Medical Sciences,Zahedan, IR Iran.
authors.forename: Ramazan
authors.initials: R
authors.lastname: Mirzaei
authors.affiliation: Department of Anatomical Sciences, School of Medical Sciences, Tarbiat Modares University, Tehran, IR Iran.
authors.forename: Mojdeh
authors.initials: M
authors.lastname: Salehnia
authors.affiliation: Cancer Research Center, Iran Cancer Institute, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Ahad
authors.initials: A
authors.lastname: Muhammadnejad
keywords: Cochlear Hearing Loss; Histological Technique; Inner Auditory Hair Cell