RESUMO
OBJECTIVES/HYPOTHESIS: The purpose of this study was to investigate possible preventive effects of anti-intercellular adhesion molecule-1 antibody (anti-ICAM-1 Ab) on noise-induced cochlear damage as assessed by changes in auditory thresholds and cochlear blood flow. STUDY DESIGN: A controlled animal study. Pretreated rats with anti-ICAM-1 Ab or saline control, followed with exposure to 72 continuous hours of broad band noise (107 dB SPL), and 24 hours after noise exposure treated again with anti-ICAM-1 Ab or saline. METHODS: Eighteen healthy male Fischer rats (200-250 g) were used. Sixteen were randomly selected to study noise-induced temporary threshold shifts. The remaining two rats were used to study cochlear blood flow (CBF), using laser Doppler flowmetry and blood pressure measurements. RESULTS: Rats treated with anti-ICAM-1 Ab (1.875 mg/kg, intravenously) showed attenuated temporary threshold shifts (TTS) compared to controls. Both groups showed a partial threshold recovery 72 hours following noise exposure, normal for this noise exposure paradigm. Comparisons of baseline and post-treatment measurements of CBF and mean arterial blood pressure revealed no significant changes. Anti-ICAM-1 Ab animals displayed significantly lower mean auditory threshold shifts at all five test frequencies (P < .05) when compared to control. CONCLUSIONS: Blocking the cascade of reactive oxygen species (ROS) generation by using anti-ICAM-Ab protects against noise-induced hearing loss.