The prophylactic effect of thyroxin on kanamycin ototoxicity in guinea pigs.
Guinea pigs receiving intramuscular kanamycin sulfate 400 mg/kg daily and thyroxin 10 mg/kg orally every other day for 9 days were studied to determine whether thyroxin prevents toxic damage to the cochlea from kanamycin. The auditory brainstem response thresholds of wave IV evoked by tone pip stimuli at 4 and 8 kHz were found to be 19.1 dB and 27.2 dB poorer, respectively, for the kanamycin-only animals. Less than 10% of outer hair cells were damaged in 80% of basal turns but without any involvement in the rest turns in animals given thyroxin. Over 50% of outer hair cells were damaged in 65.4% of basal turns and over 50% of the second and third turns were also involved in the kanamycin-only group. Our study suggests that thyroxin reduces the accumulation of kanamycin in the perilymph and prevents the ototoxicity of kanamycin.
Hangfu
M
M
Department of Otolaryngology, Ren Ji Hospital, Shanghai Second Medical University, People's Republic of China.
Zhao
J
J
Din
D
D
D000818:Animals; D001309:Auditory Threshold / Q000187:drug effects*; D003051:Cochlea / Q000187:drug effects* / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects*; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D007273:Injections, Intramuscular; D007612:Kanamycin / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D010498:Perilymph / Q000378:metabolism; D013974:Thyroxine / Q000008:administration & dosage / Q000494:pharmacology*
D007612:Kanamycin; D013974:Thyroxine