Scanning and transmission electron microscopic observation of cochlear hair cell injuries of guinea pig exposed to blast underpressure

Objective To explore ultrastructural characteristics of the cochlear hair cells in guinea pig exposed to blast underpressue(BUP).Methods The guinea pigs were killed 8h to 7d after exposure to experimental BUP,and their temporal bones were removed for fixation and ultrastructural observation using scanning and transmission electron microscope.Results The ultrastructure of the cochlear hair cells in the guinea pigs appeared obvious damages following exposure to BUP at peak underpressure between-22.4kPa and-63.3kPa.The second and third rows of outer hair cells were more severely damaged than the first row of outer hair cells.The most significant findings in transmission electron microscopy were depolymerization of actin filiaments with stereocilla,swelling of submembraneous cistern.The cytoplasmic changes were various changes of mitochondria,formation of vacuoles,and irregularly arranged stereocilia.Conclusion The exposure to BUP may induce pathological changes of the OHCs ultrostructure in guinea pigs.And that,the higher the peak of underpressure,the severer these ultrastuuctural changes.