PRENATAL PARTICLE EXPOSURE ENHANCES PERSISTENT INWARD CURRENTS IN MIDDLE AGED MICE

By 2050, more than 150 million people worldwide will be living with neurodegenerative diseases (NDDs). While familial cases account for a small proportion of cases, most cases are sporadic. Increasing evidence implicates exposure to air pollution particles as a risk factor. Additionally, neuronal hyper-excitability is a key feature of almost all NDDs, and one of the earliest changes is increased persistent inward currents (PICs), detectable already before disease onset.
Here, we investigate the effects of maternal exposure to carbon black nanoparticles (CBNPs) on neuronal excitability and NDD development in prenatally exposed male and female mice. Time-mated C57BL6 mice were exposed to CBNPs four times during gestation by maternal intratracheal instillation. Behaviour was tested at 1.5 and 7 months, and neuronal excitability was assessed using in vivo recordings of spinal motoneurons at 9 months.
At 1.5 months, no effects were detected in locomotor, exploratory behaviour or in sensorimotor gating in exposed compared to control offspring. At 7 months, no alterations were seen in locomotor, exploratory behaviour, sociability, episodic memory, nor motor function. At 9 months, electrophysiology recordings showed no deficits in repetitive firing ability with normal rheobase and I-f gain in the primary range; however, a significantly lower onset of the secondary range of firing indicated increased PICs in prenatally exposed mice.
Prenatal exposure to CBNPs appears to enhance the onset of PICs in middle-aged mice prior to any obvious changes in animal behaviour. This may contribute to a later increased vulnerability to NDDS.