Lifelong Impact of Prenatal Stress: Exacerbated Memory Impairments and Gene Expression Changes Under Adult Chronic Stress.

INTRODUCTION

Chronic stress can have significant impacts on both physical and mental health, including affecting learning and memory processes. Research has shown that exposure to stress during prenatal and neonatal stages can have long-lasting effects on individuals. The objective of this study is to investigate how prenatal stress influences an organism's response to adult stress in terms of memory and learning processes. This comprehensive approach aims to examine the impact of prenatal and adult stress on cognitive functions and gene expression in specific brain regions.

METHODS

The study involved subjecting pregnant female rats to restraint stress, followed by exposing male offspring to chronic unpredictable stress (CUS) and social instability stress in adulthood for 3 weeks. The researchers then assessed passive avoidance, active avoidance, and spatial learning and memory using the shuttle box and Morris Water Maze tasks, respectively. Additionally, the expression levels of glutamate receptors, brain-derived neurotrophic factor (BDNF), tropomyosin receptor kinase B (TrkB), and Toll-like receptors (TLR2/4) genes in the rats' hippocampus and prefrontal cortex were analyzed.

RESULTS

According to our data, exposure to prenatal maternal stress led to impairments in learning and memory. These disorders are exacerbated in prenatally stressed rats exposed to adulthood stress. TLR2 and TLR4 mRNA levels were significantly elevated. In contrast, the expression of BDNF and TrkB and NMDA and AMPA receptor genes decreased compared to the control.

CONCLUSION

Collectively, these results indicate that exposure to stressors during the prenatal period is associated with potential long-term impairments in memory formation and/or retrieval, which may persist into adulthood and be exacerbated by chronic stress experienced later in life.