The role of SIRT1 protein in nucleus accumbens in relation to anxious behaviour and social dominance

Abstract

This study investigates the role of Sirt1 protein in anxiety-like behaviour and in social dominance. The purpose of the experiment was to verify whether the ablation of the protein in a specific brain region, the nucleus accumbens, could affect the behaviour of the mice in terms of social dominance and anxiety levels. 24 weaned mice were hosted in 6 separated cages, each one with four mice. Mice from three cages received a viral microinjection by stereotaxic surgery which prevented Sirt1 gene expression specifically in the nucleus accumbens, while the other ones received the same stereotaxic surgery treatment with a different virus that had no effect on the gene expression. Data obtained from light/dark box test showed a difference between the knock-down group and the control one in the latency of first entry in the light compartment. In fact, the knock-down group displayed a significantly greater latency compared with the control group. This result is related to a greater anxiety-like behaviour but was not confirmed by the other variables analysed. No interaction effect was found between Sirt1 knock-down, social dominance and anxiety but, interestingly, a significant difference emerged in the number of novel object approaches between dominant mice and subordinate ones. In fact, subordinate mice displayed a greater exploratory behaviour (more approaches to novel object) than the dominant one. We can assume from the results obtained that less concentration of Sirt1 protein in nucleus accumbens seems to be potentially related with an anxious behavioural phenotype.