Auditory degeneration after exposure to toluene in two genotypes of mice.
Two inbred strains of mice, CBA/Ca (with a moderate hearing loss starting late in life) and C57BL/6J (with an early onset of spontaneous auditory degeneration), were exposed to toluene by inhalation (1000 ppm, 12 h/day, 7 days) at either 1 or 6 months of age. Thresholds of auditory brainstem response (ABR) were measured 3-5 days after exposure and assessed repeatedly up to the age of 16 months (C57) or 23 months (CBA). Both strains of mice exposed to toluene at 1 month of age showed a mild loss of sensitivity at a high frequency (31.5 kHz) shortly after exposure. With increasing age, toluene exposure had little effect on the aging process of the auditory system in CBA mice but accelerated age-related hearing loss in C57 mice. The results indicate that toluene exposure can aggravate auditory deterioration only in mice with a strong genetic predisposition to spontaneously precocious age-related hearing loss.
Li
H S
HS
Department of Physiology II, Karolinska Institute, Stockholm, Sweden.
Johnson
A C
AC
Borg
E
E
Höglund
G
G
D000280:Administration, Inhalation; D000818:Animals; D001933:Brain Stem / Q000187:drug effects; D005838:Genotype; D006309:Hearing / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL / Q000235:genetics*; D008808:Mice, Inbred CBA / Q000235:genetics*; D012684:Sensory Thresholds; D014050:Toluene / Q000008:administration & dosage / Q000633:toxicity*
D014050:Toluene