Investigating the impact of perinatal EMF exposure and nitric oxide modulation on rat brain development: a histological analysis of neuronal alterations and GFAP expression

Abstract

The environment in which we develop can have profound but subtle impacts on a multitude of biological systems. Small changes in this environment during prenatal development, such as the presence of an electromagnetic field (EMF) have been shown previously to have the ability to alter the neurobiology and behaviour of humans and animals. The present study builds on current knowledge of environmental influences by investigating the impact of nitric oxide (NO) modulation and EMF exposure on neurodevelopment. During a previous study rats were exposed perinatally to either water, 1g/L of L-arginine (LA), or 0.5g/L of N-methylarginine (NMA) and a 7Hz square wave EMF at three separate intensities (0nT, ≤50nT, and 500nT) starting ~3 days prior to birth and completing 14 days after. They were then allowed to develop until adulthood and their brains were harvested (Mean age=568.17 days, SD=162.73). While the prior study focused primarily on behaviour, the present study examined possible changes to the neurobiology by looking at alterations in neuron counts and glial fibrillary acid protein (GFAP) expression. Results of which, highlight significant changes in multiple brain areas including the amygdala, hippocampus, cortices, and hypothalamus, resulting from NO modulation and EMF exposure. Particularly, exposure to EMF resulted in a significant increase in neurons within the right secondary somatosensory cortex along with a significant increase in the average length of branches on GFAP-expressing cells in the right ventromedial hypothalamus. Additionally, sex-specific interactions with the EMF exposures were observed in the hippocampus where females exposed to the EMF had a significant increase in the number of neurons within the left CA3 compared to males. However, the EMF exposure elevated the number of branches on GFAP-expressing cells in the left CA2 of male rats. These results point to an intricate interaction-based relationship between sex, hemisphere, NO modulation and EMF exposure during developmental periods.