Research On Hearing The Health Effects Of Oxygen Plateau Environment

Object: The present research aimed to give a system analysis on the possible relationship between hearing changing and altitude hypoxia of people by epidemiological survey system. By establishing animal model, the research studied how the settling time on highland affect the auditory system, which can provide the theoretical basis for deafness treatment caused by oxygen deficit.Method: 1. By random cluster sampling method, 200 young people between 18 to 25 in Lhasa were investigated by questionnaire survey and pure tone test and were screened about hearing by international standard. The possible relationship between hearing changing and altitude hypoxia of people will be analyzed by statistical knowledge.2. using animal model test: By random selection on 140 Wistar mice with normal hearing(male 70 and female 70, aging from 3 to 4 months, weighing 200 g to 300g), index changes were recorded ranging from one to six months after arriving highland. The index of mice arriving first day was a control group. Make stretched preparation on cochlea under an dissecting microscope and have hematoxylin dyeing. In the way of observation and counting at 400 times magnification, the influence on cochlear HC cells by anoxic environment in different time arriving highland will be analyzed.Results: 1. Among the 200 people investigated, hearing loss rate was 13.0%(26/200). The male prevalence(24.0%, 18/75) was apparently higher than that of female(6.4%, 8/125). The difference was statistically significant(P<0.05). The prevalence of Tibetan people was 17.3%(20/115), higher than that of Han people(7.1%, 6/85). The difference was also statistically significant(P<0.05).2. Mice arriving highland suddenly showed a certain acute symptoms of altitude sickness. With time arriving highland and continuous hypoxia environment, a large number of experimental mice were significantly decreased activity, body hair became rough even shed, the amount of drinking and food intake reduced, some mice appeared failure phenomena of the body. Among the experiment mice from 10 to 180 days arriving highland, 15 mice had died. And 6 appeared the monocular or binocular blindness phenomenon after arriving highland 2 months.3. From the result, hair cells within the cochlea wasn`t changing obviously during the first three months. However, with prolonged hypoxia time, OHC appeared some phenomena, cells enlarged, became deform and displacement, cell spacing widened, became blurry even disappeared. IHC also had some morphological changes with OHC changes.Conclusion: 1. Long-term survival in hypoxia environment has a certain effect on human visual and hearing function.2. People in remote areas of Tibet have serious hearing loss situation, which should be paid enough attention.3. Highland hypoxia environment can make some damage to hearing system of human being.4. The damage to cochlear by hypoxia environment starts from bottom to the top. Damage to cochlear hair cells starts from OHC cells, then IHC cells will be damaged.