Sensitive developmental periods for kanamycin ototoxic effects on distortion-product otoacoustic emissions.
The developing rat is hypersensitive to aminoglycoside toxicity, which is expressed early on as a destruction of outer hair cells (OHC). In the current study, distortion-product otoacoustic emissions (DPOAE), which specifically measure the micromechanical activity of OHCs, were used to assess functional effects of administering a regimen of kanamycin to three groups of neonatal rats representing discrete postnatal developmental periods. In this manner, pigmented rats were treated at postnatal days 1-10, 11-20, and 21-30. A series of input-output (I/O) functions obtained for the 2f1-f2 DPOAE during the post-treatment period indicated that detection thresholds were significantly elevated for the animals treated on postnatal days 1-10 and 11-20, with the greatest elevations observed at the higher test frequencies.
Henley
C M
CM
Department of Otorhinolaryngology/Communicative Sciences, Baylor College of Medicine, Houston, TX 77083, USA. chenley@bcm.tmc.edu
Weatherly
R A
RA
Martin
G K
GK
Lonsbury-Martin
B
B
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000633:toxicity*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D018072:Hair Cells, Auditory, Outer / Q000166:cytology / Q000187:drug effects*; D007612:Kanamycin / Q000008:administration & dosage / Q000633:toxicity*; D017084:Otoacoustic Emissions, Spontaneous; D011247:Pregnancy; D051381:Rats
D000900:Anti-Bacterial Agents; D007612:Kanamycin