Enriched environment treatment remediated hippocampal monoamine neurotransmitters and emotional deficits in offspring induced by maternal chronic stress rat during pregnancy

Early life environment affect the normal development of the mood in the process of infant development and increase the risk of mental disorder diseases. The aim of current study was to investigate enriched environment can repair emotional deficits in offspring rats induced by maternal chronic stress during pregnancy, explore the molecular mechanisms from the changes of monoamine neurotransmitters, dopamine (DA), norepinephrine (NE) and serotonin (5-hydroxytryptamine; 5-HT) in the hippocampus. A rat model of maternal chronic stress during pregnancy was mating from 3rd day during subjected to chronic unpredictable mild stress (CUMS). Offsprings were weaned on day 21 and housed under either standard or enriched environment 30 days. Plasmacorticosterone levels of maternal rats and their offspring were determined by radioimmunoassay. The body weights were recorded in PND 21 and PND 50. Emotional responses were tested using open-field test (OFT), sucrose preference test (SPT) and tail of suspend test (TST). The levels of DA, NE and 5-HT in hippocampus of all experimental animals were detected using enzyme-linked immunoassay kit. Results indicated that an elevation was observed in the plasma corticosterone level of rat model of maternal chronic stress during pregnancy. Enriched environment treatment reduced offspring’s plasma corticosterone level and improved their body weight, changed the emotional function, increased the level of hippocampal NE, DA and 5-HT in OPS group. Collectively, these findings disclose that increasing of hippocampal monoamine neurotransmitters and decreasing of corticosterone in offspring after enriched environment might be the possible cause for emotional dysfunction induced by maternal chronic stress rat during pregnancy.