Early behavioral effects of lead perinatal exposure in rat pups

Area of Science:

• Developmental toxicology
• Neurobehavioral toxicology
• Auditory communication

Background:

• Infant crying analysis can indicate effects of prenatal and perinatal lead exposure on the central nervous system.
• Ultrasonic vocalizations (USV) are crucial early behaviors in rat pups, essential for development.
• Understanding lead's impact on USV can reveal early neurodevelopmental alterations.

Purpose of the Study:

• To evaluate how low-level lead exposure during perinatal and early postnatal periods affects rat pup ultrasonic vocalizations (USV).
• To determine if USV can serve as an early indicator of central nervous system damage from lead.
• To investigate developmental changes in USV emission following lead exposure.

Main Methods:

• Female rats were administered daily doses of lead acetate (8, 16, or 24 mg/kg) or a control solution for 30 days before breeding and throughout pup weaning.
• Pups experienced lead exposure during pregnancy+lactation, pregnancy only, or lactation only via dam crossover.
• Measurements included USV, locomotion, rectal temperature, body weight, and blood lead levels on postnatal days 7 and 14.

Main Results:

• Lead exposure during pregnancy+lactation, pregnancy, or lactation significantly decreased USV in 7-day-old pups in a dose-dependent manner.
• Conversely, lead exposure during different pregnancy phases significantly increased USV in 14-day-old pups, also dose-dependently.
• Blood lead levels ranged from 5.7 to 36.5 microg/dl; body weight and temperature were unaffected, but 14-day-old pups showed increased activity.

Conclusions:

• Low-level lead exposure during critical developmental periods induces significant, age-dependent changes in rat pup ultrasonic vocalizations.
• USV alterations in rat pups exposed to lead suggest potential neurodevelopmental impacts.
• This study highlights USV as a sensitive measure for detecting early neurotoxic effects of lead.