Traffic-related particulate matter affects behavior, inflammation, and neural integrity in a developmental rodent model

• Published in: Environmental research 2020-04, Vol.183, p.109242-109242, Article 109242
• Main Authors: Nephew, Benjamin C., Nemeth, Alexandra, Hudda, Neelakshi, Beamer, Gillian, Mann, Phyllis, Petitto, Jocelyn, Cali, Ryan, Febo, Marcelo, Kulkarni, Praveen, Poirier, Guillaume, King, Jean, Durant, John L., Brugge, Doug
• Format: Article
• Language: English
• Subjects: Animals; Anxiety - etiology; Autism Spectrum Disorder - epidemiology; Behavior; Boston; Development; Disease Models, Animal; Female; Inflammation; Lactation; Male; Nervous System - drug effects; Particulate matter; Particulate Matter - toxicity; Rats; Rodent; Rodentia; Social Behavior; Vehicle Emissions - toxicity
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2020.109242

Recent studies indicate that exposure to airborne particulate matter (PM) is associated with cognitive delay, depression, anxiety, autism, and neurodegenerative diseases; however, the role of PM in the etiology of these outcomes is not well-understood. Therefore, there is a need for controlled animal studies to better elucidate the causes and mechanisms by which PM impacts these health outcomes. We assessed the effects of gestational and early life exposure to traffic-related PM on social- and anxiety-related behaviors, cognition, inflammatory markers, and neural integrity in juvenile male rats. Gestating and lactating rats were exposed to PM from a Boston (MA, USA) traffic tunnel for 5 h/day, 5 days/week for 6 weeks (3 weeks gestation, 3 weeks lactation). The target exposure concentration for the fine fraction of nebulized PM, measured as PM2.5, was 200 μg/m3. To assess anxiety and cognitive function, F1 male juveniles underwent elevated platform, cricket predation, nest building, social behavior and marble burying tests at 32–60 days of age. Upon completion of behavioral testing, multiple cytokines and growth factors were measured in these animals and their brains were analyzed with diffusion tensor MRI to assess neural integrity. PM exposure had no effect on litter size or weight, or offspring growth; however, F1 litters developmentally exposed to PM exhibited significantly increased anxiety (p = 0.04), decreased cognition reflected in poorer nest-organization (p = 0.04), and decreased social play and allogrooming (p = 0.003). MRI analysis of ex vivo brains revealed decreased structural integrity of neural tissues in the anterior cingulate and hippocampus in F1 juveniles exposed to PM (p