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Updated: Aug 4, 2026
Using Chronic Social Stress to Model Postpartum Depression in Lactating Rodents
Published on: June 10, 2013
Low level lead exposure during lactation increases rough and tumble play fighting of juvenile rats
Insights
Early lead exposure in lactating rats altered juvenile social behaviors, specifically increasing play fighting and social investigation. These changes highlight the sensitivity of social interactions to developmental toxicity.
Area of Science:
- Neuroscience
- Developmental Toxicology
- Behavioral Science
Background:
- Lead exposure during early development is a significant public health concern.
- Assessing the subtle neurobehavioral effects of developmental lead exposure is crucial.
Purpose of the Study:
- To investigate the impact of developmental lead exposure on social interactive behaviors in juvenile rats.
- To determine if social behaviors can serve as sensitive indicators of early-life toxicant exposure.
Main Methods:
- Lactating rats received either water or lead chloride solution (500 ppm lead) from postnatal Days 1-21.
- Offspring behaviors, including social investigation and play fighting, were assessed on Days 26 and 36.
- Activity levels and responses to a non-playful stimulus were also recorded.
Main Results:
- Lead exposure did not affect maternal fluid intake, pup growth, or maternal behaviors.
- Juvenile rats exposed to lead exhibited increased play fighting (crossover, pinning) and social investigation.
- Increased crossover frequencies were observed when lead-exposed subjects interacted with a non-playful stimulus.
- General activity levels remained unaffected by lead exposure.
Conclusions:
- Developmental lead exposure can subtly alter juvenile social interactive behaviors without impacting general activity or growth.
- Social behaviors, particularly play fighting and investigation, are sensitive endpoints for detecting early-life toxicant exposure.
- Social interaction paradigms offer a valuable tool for assessing neurodevelopmental toxicity.
Abstract:
Lactating rats were given distilled water or distilled water containing 0.067% lead chloride (500 ppm lead) as their sole source of drinking fluid from Days 1-21 of lactation. Activity, social investigation and rough and tumble play fighting behaviors of the offspring were observed on Day 26 and activity and play solicitation behaviors on Day 36. Although lead treatment reduced the mothers' fluid intake, there were no effects on pup growth and activity or on maternal behaviors. When paired with a group-housed stimulus animal on Day 26, lead-treated subjects had increases in the two measures of play fighting (crossover and pinning), and in social investigation, relative to controls. When tested with a scopolamine-treated, non-playful stimulus on Day 36, increased crossover frequencies were observed in lead-treated subjects when compared with controls. Two-min activity levels on Days 26 and 35 were unaffected by lead exposure. These results indicate that social interactive behaviors of juvenile rats are effective tools in the assessment of exposure to toxic substances early in development.
