A dual behavioral and electrophysiological evaluation of the sodium salicylate induced tinnitus model in rats: Comparing click and chirp stimuli in auditory brainstem responses

Animal models are essential for investigating tinnitus physiology and therapeutic interventions. This study aimed to evaluate a salicylate-induced tinnitus rat model using a dual behavioral-electrophysiological approach and to compare the sensitivity of click and chirp stimuli in auditory brainstem responses (ABRs). Following sound-silence conditioning in a water T-maze (WTM), the salicylate group received sodium salicylate (300 mg/kg, i.p.) for six days, while the sham group received 0.9% saline. Tinnitus presence was behaviorally assessed via the water T maze swimming test, followed by ABR recordings under anesthesia using click and chirp stimuli at 80 dB SPL (waves I-V) and 20 dB SPL (wave II for hearing loss evaluation). Twenty-four male Sprague-Dawley rats with normal hearing were analyzed to sham (n = 13) and salicylate (n = 11) groups. Behaviorally, rats in the salicylate group spent significantly more time in the sound-associated arm during silence, demonstrating tinnitus-like behavior. Electrophysiologically, salicylate administration induced significant amplitude increases in waves III exclusively in click-evoked ABRs. Conversely, chirp-evoked ABR amplitudes showed no alterations post-salicylate exposure. In the latency analyses, while the three-way interaction was not significant. The stimulus x time two-way interaction was found to be statistically significant only for wave V. In conclusion, combining Water T-Maze testing with ABR recordings offers a time-efficient and animal-welfare-oriented approach to evaluate experimental tinnitus. Under the present recording conditions, click-evoked ABRs captured amplitude alterations more responsively than chirp stimuli in this specific acute model, though further research is required before click stimuli can be established as a generally superior marker for tinnitus assessment.