Objective To study
cochlear hair cell
pathology induced by Neomycin ototoxicity during postnatal development in rats
by means of
scanning electron microscopy(SEM). Methods Seven-day-old rats were treated intramuscularly
with Neomycin 80 mgkg1d-1 for 8 successive days and were allowed to survive seven days
before sacrifice and preparation for observation by SEM. Results Neomycin induced severe
damage on
cochlear hair cell during postnatal development of rats.Three rows of outer hair
cells (OHCs)in the basal turn and hook
region were lost and OHCs in apical turn were also
affected.The disoriented or partly disappeared stereocilia of inner hair cell(IHC)and loss of IHC
were observed in the basal turn and hook region.Epithelium of the former OHC region was
replaced by polygonal cells with a tuft of microvilli at their apical surface,which were similar to
the early stage of embryonic development of cochlear hair cells.Regenerated hair cells were
not found in the damaged region of the sensory epithelia. Conclusion Cochlear hair cells were
more sensitive to the ototoxic effects of Neomycin during postnatal development in rats.The
polygonal cells toped with a tuft of microvilli appeared in the damaged region indicated that
auditory receptors showed an attempt to regenerate.