Abstract
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.
Lingua originale | English |
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pagine (da-a) | 378-386 |
Numero di pagine | 9 |
Rivista | OTOLOGY & NEUROTOLOGY |
Volume | 39 |
DOI | |
Stato di pubblicazione | Pubblicato - 2018 |
Keywords
- Acoustic trauma
- Cochlea
- Inner ear
- Polyphenol