Effects of Compound Factors of Simulated Weightlessness and Noise in Spaceship on Expression of Caspase-3 in Inner Ear of Guinea Pigs
WU Wei
HAN Hao-lun
YU Meng
WANG Fang-yuan
QU Chang-bei
ZHANG Jian-zhong
WANG Hong-nan
LI Bao-wei
WANG Gang
MEMG Ling-zhao
WANG Pu-jie
YU Xue-jun
WU Da-wei
NIU Cong-min
LIU Gang
Abstract：Objective To investigate the effects of compound factors of simulated weightlessness and noise in space-ship on auditory function and the expression of apoptotic marker Caspase-3 in the inner ear of guinea pigs. Methods Thirty six guinea pigs were randomly divided into a control group (n=6), a simulated weightlessness group (Group A, n=10), a noise exposure group (Group B, n=10) and a weightlessness with noise group (Group C, n=10). Weightlessness was simulated by suspending the posterior limb. Noise exposure was simulated to the noise environment in a spaceship. Bilateral auditory brainstem response (ABR) thresholds were tested prior to and immediately after exposure and after 3-days of recovery. Co- chleae were harvested immediately after exposure or after 3 days of recovery. Immunohistochemistry staining was used to ex-amine expression of the apoptotic marker Caspase-3 in hair cells, stria vascularis and spiral ganglion cells. Results Immedi-ately after exposure and after 3 days of recovery, ABR thresholds of Group A were significantly lower than those of Groups B and C (P<0.05), whereas there was no significant difference between Groups B and C (P>0.05). Pre- vs post-exposure ABR changes in Group A were different from Groups B and C (p<0.05), but not between Groups B and C (P>0.05). ABR changes before and after recovery,in Group B were significantly different from Groups A and C (p<0.05), but not between Groups A and C (P>0.05). Caspase-3 expression was positive in hair cells and stria vascularis both immediately after exposure and af-ter 3-days of recovery. The expression was relatively strong in spiral ganglion cells immediately after exposure in Groups A and C, but weak in Group B. After 3-days of recovery, the expression turned negative in Group A, but increased in Groups B and C compared to immediately after exposure. Conclusion Weightlessness and simulated noise exposure in spaceship both can result in increased ABR thresholds in guinea pigs. When compounded, noise exposure may play a leading role in affecting hearing. Compared with the noise exposure, weightlessness may slow down the recovery of hearing loss. The hear-ing loss induced by compounded noise and weightlessness was appears to be closely related to apoptosis of hair cells, stria vascularis and spiral ganglion cells in the inner ear.
Keywords：noiseweightlessnessinner earapoptosiscaspase-3
Publication Date：2013-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 451-456 )