Effect of Acute and Chronic Salicylate Induced Tinnitus on Social Interactions and Aggressive Behaviors in Male Rats

Abstract

Background and Aim: Many people with tinnitus have significant difficulties in social interactions. It is not clear whether impaired social interactions are a direct consequence  of tinnitus or not. Due to the possibility of controlling longitudinal data in animal studies (pre- and post-tinnitus induction and duration), this study aimed to examine the effects of acute and chronic salicylate induced tinnitus on social interactions and aggressive behaviors in rats.

Methods: In this study, 28 male Wistar  rats  with  normal  hearing  were  divided  into two groups: acute tinnitus (7 received saline, and 7 received single dose of 400 mg/kg salicylate) and chronic tinnitus (7 received saline, and 7 received 400 mg/kg salicylate for 14 consecutive days). The auditory brainstem response, pre-pulse inhibition of acoustic startle, gap pre-pulse inhibition, and social interaction tests were conducted at baseline, 6 hours after salicylate injection in the acute group and one day after salicylate injection in the chronic group.

Results: The gap pre-pulse inhibition of acoustic startle significantly decreased after both acute and chronic salicylate toxicity. Following number and time and struggling number and time after salicylate injection were significantly different in both groups, while Sniffing, wounding, attacking and fisting numbers significantly increased only in the chronic salicylate group. Results of saline group were not significant.

Conclusion: Tinnitus caused by either acute or chronic salicylate toxicity may have an effect on social and aggressive behaviors. Since rats’ aggressive behaviors increased following chronic tinnitus induction, it can be said that the duration of tinnitus is also effective.

Keywords: Tinnitus; salicylate; pre-pulse inhibition; social interaction test; aggressive behavior