LTC Lorraine Babeu
The purpose of this study was to evaluate if an antioxidant (U74389G) has a protective effect against the combined ototoxicity of exposure to noise and chloroquine. Fifty-six pigmented guinea pigs were divided into eight groups. The animals received one or combinations of the following treatments: daily 1 ml subcutaneous injection of chloroquine diphosphate in saline (35 mg/ml) for five consecutive days, a .3 ml oral solution of antioxidant U74389G in citrate NaCl twice daily for three days, and exposed to 93 dB SPL of broadband noise for 48 hours. Auditory brainstem response (ABR) to tone bursts at 4, 8, 12 & 16 kHz and clicks were recorded at three periods. The first was baseline. The second measurement (post-treatment) was taken at the end of the 48 hours of noise exposure and the third measurement (recovery) was taken 24 hours after the second measurement. The ABR measurements indicated that chloroquine appeared to create some change in hearing sensitivity. The antioxidant appeared to have a protective effect against the combined ototoxic effects of chloroquine and noise exposure. In the antioxidant and noise exposure condition the antioxidant did not decrease the amount of the threshold shift but it appeared to aid in the recovery from noise exposure.