The functional state of the auditory analyzer in the conditions of modeling acute acoustic trauma in Wistar rats

Introduction. Assessment of the functional state of the auditory analyzer under the conditions of the acute acoustic injury model allows us to develop adequate ways to prevent hearing loss at different stages of medical care.

The aim of the study. To evaluate the functional state of the auditory analyzer by recording short-latency auditory evoked potentials under the therapeutic effect of dexamethasone in modeling acute acoustic trauma.

Materials and methods. The study was performed on 6 rats (12 ears) Wistar drain, males, 300-320 g. The acute acoustic injury was simulated in a soundproof chamber by applying a tone frequency of 5 kHz at an intensity of 118-120 dB at the animal's ear for 2 hours. The therapeutic effect of dexamethasone administered intravenously at a dose of 1.7 mg/kg in a volume of 1 ml 2 hours after the end of acoustic stimulation was studied. SLAEP was studied with monoaural ipsi stimulation with tones of 20 and 30 kHz in a free sound field. The hearing threshold, amplitude, and latency of the II peak of the SLAEP complexes were evaluated initially, on the 1st and 7th days after acute acoustic injury.

Results and discussion. Acoustic stimulation of Wistar rats led to persistent depression of audiological parameters: an increase in VSWR thresholds and an inhibition of the amplitude of the II peak when a tonal stimulus of 30 kHz was applied (p<0.05). The introduction of dexamethasone in the treatment regimen after acute acoustic injury modeling does not lead to a complete restoration of audiological parameters.

Conclusion. A technique is presented that makes it possible to perform objective audiometry on domestic equipment in experimental animals (rodents) in accordance with their specific auditory sensitivity. The insufficient effect of restoring auditory function after intravenous dexamethasone administration is the basis for the development of more advanced glucocorticosteroid delivery systems to protect the auditory analyzer.