Perinatal cannabidiol exposure reshapes astrocyte morphology and tripartite synapse organization in a sex-dependent manner
Cannabidiol (CBD) has recently gained significant public acceptance as a safe therapeutic, contributing to increased use during pregnancy. However, little is known about how maternal CBD exposure impacts fetal brain development. Here, we established a preclinical CBD perinatal exposure (CBD-PCE) model to examine the impacts of CBD on astrocyte morphology in the medial prefrontal cortex (mPFC), a brain region critical for working memory and affective behaviors. Astrocytes play critical roles in maintaining ionic/metabolic homeostasis, neurotransmission, and neurovascular coupling in the CNS. They exhibit highly ramified processes with endfeet surrounding synapses, forming tripartite synapses. We quantitatively assessed the impact of CBD-PCE on astrocyte morphology and the composition of tripartite synapses in mPFC using high-resolution three-dimensional (3D) imaging. Our morphometric analyses revealed that CBD-PCE reduced astrocyte density and increased the number of major branches and whole-cell volume in the mPFC of male, but not female, progenies. Using high-magnification 3D analysis, we found that mPFC astrocytes after CBD-PCE exhibited increased neuropil infiltration volume and reduced surface-to-volume ratios in males but not in females. Moreover, the levels of aquaporin-4 (AQP4) and Kir4.1 inwardly rectifying potassium channel, two key components in regulating ionic homeostasis, are elevated on the membranes of male CBD-PCE astrocytes. We also analyzed mPFC tripartite synapses and observed significant increases in thalamocortical tripartite synapse density in both sexes, whereas intracortical excitatory synapses were reduced only in females. Collectively, these findings demonstrate that CBD-PCE induces sex-specific changes in astrocyte morphology and in the composition of tripartite synapses in the mPFC of the progenys brains.