The Antioxidant Effect of Rosmarinic Acid by Different Delivery Routes in the Animal Model of Noise-Induced Hearing Loss

Anna Rita Fetoni*, Sara Letizia Maria Eramo, Antonella Di Pino, Rolando Rolesi, Fabiola Paciello, Claudio Grassi, Diana Troiani, Gaetano Paludetti

*Corresponding author

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


HYPOTHESIS: Trans-tympanic Rosmarinic Acid (RA), as compared with the systemic administration, protects against noise-induced auditory hair cell and hearing losses in rats in vivo. BACKGROUND: ROS production, lipoperoxidative damage, and an imbalance of antioxidant defences play a significant role in noise-induced hearing loss. Several molecules with antioxidant properties have been tested to restore redox homeostasis; however, drug delivery system represents a challenge for their effectiveness. In our model, acute and intense noise exposure induces hearing loss, hair cell death, and oxidative stress, with an increase in superoxide production and over-expression of lipid peroxidation in cochlear structures. METHODS: RA was administrated in male Wistar rats by trans-tympanic (20 μl) and systemic (10 mg/kg) modality. In systemic administration, RA was injected 1 hour before noise exposure and once daily for the following 3 days. ABRs were measured before and at days 1, 3, 7, and 30 after noise exposure. Rhodamine-phalloidin staining, dihydroethidium and 8-isoprostane immunostainings were performed to assess and quantify outer hair cells loss, superoxide production, and lipid peroxidation in the different experimental groups. RESULTS: Systemic RA administration significantly decreased noise-induced hearing loss and the improvement of auditory function was paralleled by a significant reduction in cochlear oxidative stress. The trans-tympanic modality of drug administration showed a similar degree of protection both at the functional and morphological levels. CONCLUSION: The effectiveness of RA given via trans-tympanic injection could be interesting for the future application of this minimally-invasive procedure in the treatment of ROS-induced hearing loss.
Original languageEnglish
Pages (from-to)378-386
Number of pages9
Publication statusPublished - 2018


  • Acoustic trauma
  • Cochlea
  • Inner ear
  • Polyphenol


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