Isolation Stress During the Prepubertal Period in Rats Induces Long-Lasting Neurochemical Changes in the Prefrontal Cortex

Abstract

Social isolation during postnatal development leads to behavioral and neurochemical changes, and a particular susceptibility of the prefrontal cortex to interventions during this period has been suggested. In addition, some studies showed that consumption of a palatable diet reduces some of the stress effects. Therefore, our aim is to investigate the effect of isolation stress in early life on some parameters of oxidative stress and energy metabolism (Na(+),K(+)-ATPase activity, respiratory chain enzymes activities and mitochondrial mass and potential) in prefrontal cortex of juvenile and adult male rats. We also verified if the consumption of a palatable diet during the prepubertal period would reduce stress effects. The results showed that, in juvenile animals, isolation stress increased superoxide dismutase and Complex IV activities and these effects were still observed in the adulthood. An interaction between stress and diet was observed in catalase activity in juveniles, while only the stress effect was detected in adults, reducing catalase activity. Access to a palatable diet increased Na(+),K(+)-ATPase activity in juveniles, an effect that was reversed after removing this diet. On the other hand, isolation stress induced a decreased activity of this enzyme in adulthood. No effects were observed on glutathione peroxidase, total thiols and free radicals production, as well as on mitochondrial mass and potential. In conclusion, isolation stress in the prepubertal period leads to long-lasting changes on antioxidant enzymes and energetic metabolism in the prefrontal cortex of male rats, and a palatable diet was not able to reverse these stress-induced effects.