title: Therapeutic window for ferulic acid protection against noise-induced hearing loss in the guinea pig.
abstract: CONCLUSIONS
  Our results are in agreement with the general idea that natural antioxidants achieve their best cytoprotective capacity if given before and soon after the stressor.
  
  
  OBJECTIVE
  We focused on ferulic acid (FA, 4-hydroxy 3-methoxycinnamic acid), a phenolic compound that is known to exhibit antioxidant properties. Our study was designed to evaluate the effectiveness of FA for different schedules of treatment to establish the 'therapeutic window' for FA protection.
  
  
  METHODS
  Guinea pigs were exposed to acoustic trauma (6 kHz at 120 dB for 60 min) and received a total dose of 600 mg/kg of FA. Group I, noise control; group II, noise + FA (150 mg/kg) for 4 days starting 24 h post exposure; group III, noise + FA (60 mg/kg) 1 h before and 9 days post exposure; group IV, noise + FA (60 mg/kg) given 3 days before and 7 days post exposure; group V, noise + FA (150 mg/kg) 1 h before and 3 days post noise exposure. Auditory brainstem response (ABR) test and immunohistochemical and morphological studies were performed.
  
  
  RESULTS
  Group V had significantly decreased noise-induced hearing loss at day 21 from noise exposure. The improvement of auditory function by FA was paralleled by a significant reduction in oxidative stress marker. The other schedules of drug administration showed a minor degree of protection.
authors.affiliation: Institutes of Otolaryngology, School of Medicine, Catholic University, Rome, Italy. afetoni@rm.unicatt.it
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Fetoni
authors.forename: Sara
authors.initials: S
authors.lastname: Eramo
authors.forename: Diana
authors.initials: D
authors.lastname: Troiani
authors.forename: Gaetano
authors.initials: G
authors.lastname: Paludetti
mesh_terms: D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D002452:Cell Count; D003373:Coumaric Acids / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D016057:Evoked Potentials, Auditory, Brain Stem; D016166:Free Radical Scavengers / Q000008:administration & dosage*; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000473:pathology; D006317:Hearing Loss, Noise-Induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D007150:Immunohistochemistry
chemical_list: D000447:Aldehydes; D003373:Coumaric Acids; D016166:Free Radical Scavengers; C004999:ferulic acid; C027576:4-hydroxy-2-nonenal