Multimodal preclinical study of long-term effects of prenatal ultrasound on the mouse central nervous system.

The development of the central nervous system is regulated by multiple spatio-temporally varying factors that are essential for neurons to form functional networks. Prenatal ultrasound (US) exposure may affect the dendritic arborization and spine density of CA1 neurons in the hippocampus—a key region for memory processing—but the mid- and long-term effects of this exposure are still not well understood. In this study, we used an animal model to examine how repeated prenatal US exposure impacts memory function. After treatments, we assessed the memory performance of both treated and control animals and analysed the CNS for microstructural changes in the brain tissue. We also explored potential changes in glucose metabolism and hippocampal transcriptomic profiles, focusing on calcium signaling. Our results did not reveal any changes in memory performance in US-exposed animals, despite notable microstructural impairments detected in several white matter tracts. RNA sequencing analysis revealed that US exposure causes lasting changes in calcium signaling pathways, which are known to be crucial for memory formation. Overall, our findings demonstrate that prenatal US screening in an animal model can produce enduring molecular, structural effects, underscoring the importance of further research into the safety and long-term implications of prenatal US screening.