Postpartum environmental challenges alter maternal responsiveness and offspring development

• Published in: Hormones and behavior 2020-06, Vol.122, p.104761, Article 104761
• Main Authors: Scarola, Samantha, Kent, Molly, Neal, Steven, Trejo, Jose Perdomo, Bardi, Massimo, Lambert, Kelly
• Format: Article
• Language: English
• Subjects: Amygdala - metabolism; Animals; Brain - metabolism; Brain-Derived Neurotrophic Factor - metabolism; Corticosterone - metabolism; Early life stress; Emotions - physiology; Environment; Female; Growth and Development - physiology; Hippocampus - metabolism; Limited resources; Maternal Behavior - physiology; Maternal care; Maternal resilience; Maternal responsiveness; Maternal-pup interactions; Nesting Behavior - physiology; Neuronal Plasticity - physiology; Offspring development; Postpartum Period - physiology; Postpartum Period - psychology; Pregnancy; Rats; Rats, Long-Evans
• ISSN: 0018-506X; 1095-6867; 1095-6867
• DOI: 10.1016/j.yhbeh.2020.104761

Because many threats exist in an animal's natural habitat, it is important to understand the impact of environmental challenges on maternal-offspring interactions and outcomes. In the current study, a rodent model incorporating the presence of restricted resources and an environmental threat (e.g. predator-related odors and sounds) was investigated. Specifically, pregnant females were assigned to one of four treatments: standard resources, without threat (SR; n = 7); standard resources plus threat (SR-T; n = 8); restricted resources, without threat (RR; n = 7); and restricted resources plus threat (RR-T; n = 6). Maternal rats were moved into the assigned conditions on postnatal day 2 and remained until pups were weaned. Following a standard pup retrieval task on postnatal days 2 and 6, maternal rats were exposed to a retrieval challenge task on postnatal day 8 in which each rat had to traverse a novel barrier to retrieve pups. For neurobiological measures of stress/resilience responsiveness, fecal samples were collected for detection of corticosterone and DHEA metabolites; additionally, immunohistochemistry was conducted on the maternal brains to indicate the presence of Neuropeptide Y (NPY) and Brain Derived Neurotrophic Factor (BDNF) immunoreactivity in the hippocampus, amygdala and hypothalamus. Pup development measures, including body weight and tail length, were also collected. Results suggest that maternal rats with restricted resources exhibited diminished maternal responsiveness that resulted in altered pup development measures; further, restricted resource rats exhibited endocrine markers of compromised emotional resilience (lower DHEA) and decreased neural markers of neuroplasticity (BDNF) and emotional resilience (NPY). Interestingly, predator threat affected various aspects of maternal-pup interactions but had no effect on neurobiological variables, suggesting that restricted resources had a more negative impact on maternal-related outcomes than the presence of predator threat. •Restricted resources altered maternal attention directed to offspring.•Restricted resources affected growth markers in pups.•BDNF and NPY were decreased in maternal rats exposed to restricted resources.•Resource availability altered stress and resilience hormones in maternal animals.