Strain-dependent differences in maternal care and early developmental trajectories in laboratory rats

Area of Science:

• Neuroscience
• Developmental Biology
• Animal Models

Background:

• Maternal behavior in laboratory rats is crucial for preclinical neurodevelopment models.
• Understanding strain-specific differences enhances the translational validity of research.
• Rat strains commonly used include Wistar, Sprague-Dawley (SD), and Spontaneously Hypertensive Heart Failure (SHHF).

Purpose of the Study:

• To compare maternal caregiving patterns and early offspring development across Wistar, SD, and SHHF rat strains.
• To identify strain-dependent variations in maternal behavior organization and offspring developmental trajectories.
• To assess the translational relevance of these strains for neurodevelopmental research.

Main Methods:

• Maternal behaviors were recorded from postpartum day 1-5 using frequency measures and behavioral transition network analysis.
• Offspring development was assessed from postnatal day 6-22, including growth, eye opening, reflex maturation, and ultrasonic vocalizations (USVs).
• Standardized experimental conditions were maintained across all three rat strains.

Main Results:

• Significant strain-dependent differences were observed in maternal behavior frequency and organization.
• SHHF dams exhibited reduced behavioral transitions and increased off-nest events; SD dams showed less active nursing.
• SHHF pups displayed delayed eye opening, reduced weight gain, and slower reflex maturation; both SD and SHHF pups emitted fewer ultrasonic vocalizations.

Conclusions:

• Rat strain background significantly influences early maternal care and offspring development.
• The SHHF strain presents as a valuable model for studying early-life vulnerability with translational implications.
• These findings underscore the importance of strain selection in preclinical neurodevelopmental studies.