Chronic pulmonary exposure to traffic-related fine particulate matter causes brain impairment in adult rats

• Published in: Particle and fibre toxicology Vol. 15; no. 1; pp. 44 - 17
• Main Authors: Shih, Chi-Hsiang, Chen, Jen-Kun, Kuo, Li-Wei, Cho, Kuan-Hung, Hsiao, Ta-Chih, Lin, Zhe-Wei, Lin, Yi-Syuan, Kang, Jiunn-Horng, Lo, Yu-Chun, Chuang, Kai-Jen, Cheng, Tsun-Jen, Chuang, Hsiao-Chi
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 09.11.2018; BioMed Central; BMC
• Subjects: Aging; Air Pollutants - toxicity; Air pollution; Animals; Behavior, Animal - drug effects; Brain; Brain - diagnostic imaging; Brain - drug effects; Brain - physiopathology; Brain diseases; Brain Edema - chemically induced; Brain research; Causes of; Cerebellum; Chronic exposure; Cortex (olfactory); Cytokines; Disease; Edema; Electroencephalography; Entropy; Environmental aspects; Exposure; Frequencies; Health aspects; Hippocampus; Impairment; Inflammation; Inhalation Exposure - adverse effects; Interleukin 4; Interleukins; Magnetic Resonance Imaging; Male; Memonry deficiency; Memory; Memory, Short-Term - drug effects; Neurosciences; Neurotoxicity; Neurotoxicity syndromes; NMR; Nuclear magnetic resonance; Object recognition; Olfactory bulb; Oxidative stress; Particulate emissions; Particulate matter; Particulate Matter - toxicity; Particulates; Pathogenesis; Pattern recognition; Pollution; Pollution effects; Rats; Rats, Sprague-Dawley; Risk factors; Rodents; Rotarod Performance Test; Short term memory; Shrinkage; Traffic; Traffic flow; Traffic-Related Pollution - adverse effects; Tumor necrosis factor-TNF; United States > US; Oxidative stress; Air pollution; Neurotoxicity; Inflammation; Memonry deficiency
• ISSN: 1743-8977; 1743-8977
• DOI: 10.1186/s12989-018-0281-1

Effects of air pollution on neurotoxicity and behavioral alterations have been reported. The objective of this study was to investigate the pathophysiology caused by particulate matter (PM) in the brain. We examined the effects of traffic-related particulate matter with an aerodynamic diameter of < 1 μm (PM ), high-efficiency particulate air (HEPA)-filtered air, and clean air on the brain structure, behavioral changes, brainwaves, and bioreactivity of the brain (cortex, cerebellum, and hippocampus), olfactory bulb, and serum after 3 and 6 months of whole-body exposure in 6-month-old Sprague Dawley rats. The rats were exposed to 16.3 ± 8.2 (4.7~ 68.8) μg/m of PM during the study period. An MRI analysis showed that whole-brain and hippocampal volumes increased with 3 and 6 months of PM exposure. A short-term memory deficiency occurred with 3 months of exposure to PM as determined by a novel object recognition (NOR) task, but there were no significant changes in motor functions. There were no changes in frequency bands or multiscale entropy of brainwaves. Exposure to 3 months of PM increased 8-isoporstance in the cortex, cerebellum, and hippocampus as well as hippocampal inflammation (interleukin (IL)-6), but not in the olfactory bulb. Systemic CCL11 (at 3 and 6 months) and IL-4 (at 6 months) increased after PM exposure. Light chain 3 (LC3) expression increased in the hippocampus after 6 months of exposure. Spongiosis and neuronal shrinkage were observed in the cortex, cerebellum, and hippocampus (neuronal shrinkage) after exposure to air pollution. Additionally, microabscesses were observed in the cortex after 6 months of PM exposure. Our study first observed cerebral edema and brain impairment in adult rats after chronic exposure to traffic-related air pollution.