Effects of Chronic Empathic and Reversed Empathic Stress on Anxiety-like Behaviors in Male Rats

Abstract

Background: Empathy is critical for social interactions. Nevertheless, the sharing of excessive negative emotions may affect the behaviors of the observer and demonstrator in social equality and inequality conditions. The present study investigated the effects of chronic empathic and reversed empathic stress on anxiety-like behaviors and their correlation with serum corticosterone levels in male rats. Methods: Forty-eight male Wistar rats were divided into six groups: Control, Pseudo-Observer, Pseudo-Demonstrator, Observer, Demonstrator, and Co-Demonstrator. Various types of stress included dyadic stress in social inequality conditions, such as empathic and reversed-empathic (restrained) stress, dyadic stress in social equality (receiving common stress), and single stress (restrained and unrestrained) as sham stress groups. All of these stressors were induced for 2h/day for 21 days. The time spent in the open arms and the number of entries in the open arms were measured during the elevated plus maze test to assess anxiety-like behavior. The correlations between serum corticosterone levels and OAT were evaluated for all experimental groups. Findings: The percent of total time spent in the open arms and the number of open arm entries were significantly decreased in all stressed groups. Moreover, there was a significant negative correlation between serum corticosterone levels and the percent of total time spent in the open arms in all experimental groups, except the control and pseudo-observer groups. Conclusion: According to the present findings, chronic empathic stress (observing others' psychological stress or distress) could induce anxiety in the observers. In addition, the reversed empathic stress (receiving restraint stress in the presence of a familiar cagemate in social inequality condition) can be unexpectedly effective in the induction of anxiety. It seems that the gradual changes in serum corticosterone levels play an essential role in the development of anxiety-like behaviors. © 2024 Isfahan University of Medical Sciences(IUMS). All rights reserved.