Effects of preconceptional social isolation on risk-taking behaviour and levels of neurochemical, neuroendocrine and neuroinflammatory markers in male offspring

The impact of chronic stress during the preconceptional period on the adolescent progeny has been poorly investigated. Although impulsivity and risk-taking behaviour are physiological during adolescence, they may represent key symptoms of psychiatric conditions of this life period.

Here, we evaluated the possible development of risk-taking behaviour and cognitive dysfunctions in the male offspring of socially isolated female rats, housed in control or isolation conditions (as second stressful hit) from weaning to adolescence. Underlying neurochemical, neuroendocrine and neuroinflammatory alterations were also assessed.

Increased distance travelled, time spent in the centre of an open field arena and in the open arms of an elevated plus maze were detected in the adolescent offspring of socially isolated females, together with reduced time spent in the wall, decreased latency time in the passive avoidance task and reduced discrimination index in the novel object recognition test. Elevations in glutamate levels, reduction of GABA concentrations, enhanced GLU/GABA ratio and expression of GFAP and CD11beta, as well as reduced NGF amount, were found in the prefrontal cortex of adolescent rats born from females exposed to social isolation before pregnancy. This same group showed a significant decrease of plasmatic oxytocin levels and enhanced vasopressin and prolactin concentrations, compared to controls.

In conclusion, our results point toward a detrimental effect of female exposure to chronic social stress during preconception in inducing risk-taking behaviour in the adolescent male offspring, possibly via alterations of neurochemical, neuroinflammatory and neuroendocrine pathways, thus identifying adolescence as a specific window for preventive and therapeutic approaches.