Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Anatomy and Cell Biology

Supervisor

Khokhar, Jibran

Abstract

Cannabis use is common in adolescence and there is evidence for sex differences regarding the long-term effect of cannabis use. We aimed to investigate how exposure to 3 types of cannabis vapour in adolescent rats impacts brain development using magnetic resonance imaging. Male and female Sprague Dawley rats were divided into four groups and exposed to high-CBD, high-THC, balanced CBD + THC, or air at post-natal days 28-42 using a vaporizer. In adulthood, rats underwent diffusion and functional MRI. Results indicated sex-dependent differences in the long-term effects of cannabis exposure in the adult brain. In male rats, we found a single network with altered functional connectivity amongst the four groups and two networks with altered structural connectivity amongst the four groups. In female rats, MRI results indicated no altered structural or functional networks. Adolescent cannabis vapour exposure can lead to long-lasting effects in adulthood, with males possibly being more vulnerable.

Summary for Lay Audience

As more countries legalize cannabis, there is a great availability of cannabis products, with new equipment and routs of administration. For instance, there has been a dramatic increase in cannabis vaping consumption in North America, especially among adolescents. Adolescence is a critical period for brain development and cannabis usage during this period of life might have long-term detrimental effects. Thus, this study aimed to investigate how vapor exposure to 3 types of cannabis in adolescent rats impacts brain development. We employed a technique called magnetic resonance imaging (MRI), that allows us to investigate the functionality and structure of the brain. We administered cannabis to male and female adolescent rats using a vaporizer, to simulate the rout of administration used by humans. Upon reaching adulthood, we performed MRI analysis on the rats. We found that the adult male rats exposed to cannabis in adolescence had altered brain functionality and structure in many brain regions related to cognition and emotion. On the other hand, adult female rats showed no altered brain functionality or structure. We conclude adolescent cannabis vapour exposure is related to long-term brain alterations, with males being more vulnerable than females.

Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

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