Morphological changes on cochlear hair cells of rats in simulated weightlessness and inboard noise / 北京大学学报(医学版)

ABSTRACT

Objective: To observe the morphological changes on cochlear hair cells of rats in simulated weightlessness and inboard noise and to investigate the different changes in three turns of hair cells.Methods: Thirty-two healthy SD rats, all males, were randomly divided into four groups control group, weightlessness group, noise group and weightlessness+noise groups (n=8).Then rats were exposed to-30° head down tilt as simulated weightlessness and inboard noise including steady-state noise which was (72±2) dB SPL and impulse noise up to 160 dB SPL in spaceship environment.The control group was kept in normal condition for 8 weeks.Bilateral auditory brainstem response (ABR) thresholds were tested before and after exposure respectively, and immunofluorescence staining and scanning electron microscopy (SEMs) of basilar membrane were applied after exposure.Results: ABR threshold shifts of each group were higher after exposure.There was difference between ABRs of the experiment groups before and after exposure (Pnoise group>weightlessness group>control group and the damage degree of the four turns of hair cells basal turn>mid turn>top turn.Conclusion: The rats exposed to the above environment for 2 weeks displayed obvious changes in cochlea morphology, and the weightlessness+noise group had the most obvious damage.