Chronic prenatal stress affects development and behavioral depression in rats

Area of Science:

• Neuroscience
• Developmental Psychology
• Behavioral Endocrinology

Background:

• Prenatal stress is a known risk factor for various neurodevelopmental and behavioral disorders.
• The learned helplessness model is a widely used paradigm to study depression-like behaviors in rodents.

Purpose of the Study:

• To investigate the long-term effects of chronic prenatal stress on physical development and behavioral depression in Wistar rats.
• To assess the influence of prenatal stress on the susceptibility to learned helplessness in adult male and female offspring.

Main Methods:

• Pregnant Wistar rats were exposed to chronic variable stress during the last two weeks of gestation.
• Offspring were either handled or left undisturbed, and physical development was monitored.
• Adult male offspring were subjected to the learned helplessness model to assess behavioral depression.

Main Results:

• Prenatal stress reduced male pup litter size, decreased anogenital distance, and accelerated developmental milestones (earlap, eye opening, righting reflex).
• Learned helplessness was induced in all groups except the non-stressed, handled (NS-H) group.
• Prenatally stressed, non-handled (S-NH) pups exhibited significantly longer escape latencies, indicating heightened depression-like behavior.

Conclusions:

• The employed prenatal stress paradigm effectively induced developmental changes and increased behavioral depression in adult offspring.
• Prenatal stress exposure can program offspring for increased vulnerability to depression later in life.