Auditory sensitivity in rats exposed to toluene and/or acetyl salicylic acid

The present study investigates whether exposure to acetyl salicylic acid (ASA) affects the permanent auditory loss, caused by simultaneous exposure to toluene. Rats were exposed to toluene by inhalation (1,000 ppm), or to ASA by gavage (100 mg kg-1), or to both toluene and ASA, during 10 days. Toluene exposure caused a loss of auditory sensitivity recorded as auditory brainstem response, and no loss was found after exposure to ASA alone. The group exposed to both ASA and toluene had a more severe sensitivity loss (p < 0.05) at all frequencies compared with all other groups immediately after (2-5 days) exposure and also 4 months later. The results indicate that ASA permanently potentiates toluene induced loss of auditory sensitivity.