Grant: Master's Award: Canada Graduate Scholarships

Investigating the impact acute inhalation of cannabis with a high content of delta-9-tetrahydrocannabinol has on myelination and microglia in adult and aged mice

The recent destigmatization and legalization of cannabis has contributed to a rise in consumption across the North American population. However, the molecular impact of inhaled cannabis on the healthy adult and aged brain has not been extensively researched yet. The most common compound found in cannabis is delta-9-tetrahydrocannabinol (THC). THC has been found to increase the differentiation of myelinating glial cells and improve remyelination after experimental demyelination in mice. Myelination is an essential process performed by myelinating glial cells that involves the wrapping of myelin around the axons of neurons to increase electrical transmission, which is required for proper communication in the brain. This study will explore the impact acute inhalation of cannabis has on glial cell-mediated myelination in the corpus callosum in mice (2.5 and 18-months-old). All experiments will be performed 30 minutes after exposure onset, when THC levels peak in the brain. The histological stain, Sudan Black B (2%), will be used to analyze large-scale changes in myelination. Fluorescent antibodies against myelinating glial cells will be used to analyze possible changes in their density and maturation using epifluorescence microscopy. Using fluorescent antibodies against microglia—the immune cells of the brain—followed by confocal microscopy, microglial interactions with myelinating glial cells and myelinated axons will be visualized. Lastly, using scanning electron microscopy, the ultrastructure of the myelin sheath, microglia, and microglial interactions with myelinating glial cells and myelinated axons will be quantified. This study will give insight into the impact acute inhalation of cannabis with a high content of THC has on myelination in the adult and aged brain.