Isolation Stress Exposure and Consumption of Palatable Diet During the Prepubertal Period Leads to Cellular Changes in the Hippocampus

Abstract

Social isolation is one of the most potent stressors in the prepubertal period and may influence disease susceptibility or resilience in adulthood. The glucocorticoid response and, consequently, the adaptive response to stress involve important changes in mitochondrial functions and apoptotic signaling. Previous studies have shown that consumption of a palatable diet reduces some stress effects. Therefore, the aim of the present study was to investigate whether isolation stress in early life can lead to cellular alterations in the hippocampus. For this, we evaluated oxidative stress parameters, DNA breakage index, mitochondrial mass and potential, respiratory chain enzyme activities, apoptosis, and necrosis in the hippocampus of juvenile male rats submitted or not to isolation stress during the pre-puberty period. We also verified whether consumption of a palatable diet during this period can modify stress effects. Results show that stress led to an oxidative imbalance, DNA breaks, increased the mitochondrial potential and early apoptosis, and decreased the number of live and necrotic cells. In addition, the palatable diet increased glutathione peroxidase activity, high mitochondrial potential and complex I-III activity in the hippocampus of juvenile rats. The administration of a palatable diet during the isolation period prevented the stress effects that caused the reduction in live cells and increased apoptosis. In conclusion, the stress experienced during the pre-pubertal period induced a hippocampal oxidative imbalance, DNA damage, mitochondrial dysfunction, and increased apoptosis, while consumption of a palatable diet attenuated some of these effects of exposure, such as the reduction in live cells and increased apoptosis, besides favoring an increase in antioxidant enzymes activities.

The effect of voluntary wheel running on the antioxidant status is dependent on sociability conditions

“…Oxidative protein and DNA modifications are also interesting end points to be analyzed in future studies. In line with this, rats that underwent SIS presented higher protein carbonyl levels ( Zlatković et al, 2014a ) and DNA damage ( Krolow et al, 2013 ) in the brain, suggesting that oxidation of both proteins and DNA could be an important target for SIS.…”

Enriched physical environment reverses spatial cognitive impairment of socially isolated APPswe/PS1dE9 transgenic mice before amyloidosis onset

“…Isolation stress exposure has been shown to cause cellular apoptosis in the hippocampus . Thus, we determined whether an enriched physical environment rescued hippocampal neuronal apoptosis of socially isolated APP/PS1 mice.…”

Short post‐weaning social isolation induces long‐term changes in the dopaminergic system and increases susceptibility to psychostimulants in female rats

“…In basal conditions, SI did not affect oxidative stress parameters in adult striatum, similar to the results observed above concerning dopaminergic parameters. Different reports are found in the literature relative to SI and the oxidative status: an increase in ROS production and a decrease in antioxidant enzyme activities (Arcego et al, 2013; Shao et al, 2015), or alterations in isolated parameters of oxidative stress (Krolow et al, 2013; Moller et al, 2011) have been observed. These distinct results could be due to differences in the duration of SI and the brain area studied, as well as the sex of the animals.…”