First description of behavior and immune system relationship in fish

Abstract

Considering the intriguing relationship between immune system and behavior recently described in mammals, and the lack of information of this relationship in fish, here we describe for the first time the interaction between the immune system and social and exploratory behavior in zebrafish. Fish high responders to novelty (HRN) presented a proinflammatory profile, with increased IL-1β and reduced IL-10 expression compared to fish low responders to novelty (LRN). Likewise, fish less responsive to social stimuli have a reduced expression of INF-γ. We show that fish with different behavior patterns have differences in the immune response. Our findings indicate that the interplay between immune system and behavior in zebrafish is similar to that found in mammalian models and that zebrafish should be considered as a potential model organism to study the relationship between immune system and behavior.

Zebrafish models for personalized psychiatry: Insights from individual, strain and sex differences, and modeling gene x environment interactions

“…Another commonly used zebrafish assay—shoaling test—is based on fish group behavior, since they prefer spending time with conspecifics (Green et al, ; Way, Southwell, & McRobert, ), a phenotype that can be sensitive to stress (typically tightening the shoals) and pharmacological correction (Dlugos, Brown, & Rabin, ). Furthermore, common pathological factors that affect humans (e.g., acute or chronic stress) evoke similar pathogenetic states in zebrafish, including aberrant neuroendocrine (e.g., cortisol) (Stewart et al, ) and cytokine mechanisms (Kirsten, Fior, Kreutz, & Barcellos, ; Song et al, ). Their sensitivity to clinically active anxiolytic and antidepressant drugs, such as benzodiazepines and SSRIs (Egan et al, ; Song et al, ), further supports construct and predictive validity of such zebrafish CNS models.…”

“…Assessing stable individual differences in baseline locomotor activity, principal component analyses have linked anxiety‐like responses to locomotor activity and monoamine (serotonin, dopamine) levels (Tran, Nowicki, Muraleetharan, Chatterjee, & Gerlai, ). Finally, zebrafish also show individual differences in behavioral and immune responses to stress, since “emotional” high responders to novelty stress exhibit higher proinflammatory activity (increased IL‐1β and reduced IL‐10 expression), compared to their less‐emotional low‐responder counterparts (Kirsten et al, ).…”

Divergent action of fluoxetine in zebrafish according to responsivity to novelty

“…The NOR protocol used in the present study has been previously used to distinguish HRN from LRN fish 26 . In zebrafish, the NOR test has also been used to evaluate learning and memory 27 – 29 .…”

“…In our first test, we considered as HRN the fish that did not explore the novel object at any time during the entire test and LRN fish, the ones that spent more time in the novel object zone, as described by Kirsten et al . 26 . After our initial screening, we housed fish individually, after which all HRN and LRN fish were submitted to three more NOR tests.…”

“…As made in the main experiment, we considered as HRN the fish that did not explore the novel object at any time during the entire test and LRN fish, the ones that spent more time in the novel object zone, as described by Kirsten et al . 26 . After this initial separation test, we performed an acute stress test (as described Giacomini et al .…”