Adolescent hyperactivity and impaired coordination after neonatal hyperoxia

Area of Science:

• Neuroscience
• Developmental Biology
• Pediatrics

Background:

• Preterm infants have a higher risk of attention-deficit/hyperactivity disorder and motor deficits.
• Clinical data suggest higher oxygen levels in preterm infants correlate with worse neurological outcomes.
• Experimental hyperoxia in neonatal rodents causes significant cerebral changes.

Purpose of the Study:

• To investigate the hypothesis that hyperoxia in the immature brain affects motor activity in preterm infants.
• To assess the long-term effects of neonatal hyperoxia on motor behavior and white matter integrity.

Main Methods:

• Newborn mice (P6-P8) were exposed to 48 hours of hyperoxia (80% O(2)).
• Motor activity was assessed using regular and complex running wheels starting at P30.
• Diffusion tensor imaging MRI of the corpus callosum was performed at P30 and P53.

Main Results:

• Mice exposed to neonatal hyperoxia showed increased maximum and mean running velocities in regular wheels.
• Hyperoxia-exposed mice exhibited decreased maximum velocity in complex wheels, indicating motor coordination deficits.
• Diffusion tensor imaging revealed decreased fractional anisotropy and increased radial diffusivity in the corpus callosum.

Conclusions:

• Neonatal hyperoxia induces hyperactivity and motor coordination impairments in adolescent and young adult mice.
• Hyperoxia negatively impacts white matter diffusivity in the developing brain.
• These findings suggest a link between early-life hyperoxia and long-term neurological deficits.