Influences of intense infrasound on ultrastructures of hair cells of cochlea in guinea pigs

Objective To study the influences of intense infrasound on the ultrastructural changes of the hair cells of cochlea in guinea pigs with electron microscope. Methods Thirty guinea pigs were randomly divided into five groups: control group and 4 experimental groups. The guinea pigs in experimental groups were individually exposed to 8 Hz, 12 Hz, 120 dB SPL, and 130 dB SPL in a reverberant chamber. The animals were scarified for 5 h, once a day for 4 consecutive days. The influences of intense infrasound on the ultrastructural changes of hair cells of cochlea in guinea pigs were observed by transmission electron microscope. Results The hair cells of cochlea in all experimental groups were damaged to different extent including mitochondrion denaturation, nucleus expansion, and karyopyknosis. The outer hair cells were damaged remarkably, but inner hair cells were nomal; the hair cells in 130 dB SPL group were significantly damaged compared with 120 dB SPL group. There was no difference of damage of hair cells between 12 Hz group and 8 Hz group. Conclusion The intense infrasound can cause damages with different extent to the ultrastructures of hair cells of cochlea in guinea pigs.