GSE208109
Exposure to a real traffic environment impairs brain cognition in aged mice
Traffic-related air pollution has been a common public health problem, which is associated with central nervous system dysfunction according to large-scale epidemiological studies. Current studies are mostly limited to artificial laboratory exposure environments and specific genetic mechanisms remain unclear. In the spring, we transported the aged mice from the laboratory to the 1-meter-high dry platform in the campus and tunnel at the same time. Aged mice were exposed form 7 am to 7 pm each day for 2, 4 and 12 weeks, respectively. Compared with the control group (in campus), the memory function of mice in the exposure group (in tunnel) was significantly impaired in Morris water maze. Traffic-related air pollution exposure increased the number of activated microglia in the hippocampal DG and CA1, and up-regulated mRNA expression of inflammatory factors IL-18, IL-1ß, IL-6 and TNF-a. By screening the risk genes of Alzheimer's disease, we found the mRNA and protein levels of ABCA7 were down-regulated and those of PYK2 were up-regulated in the dorsolateral prefrontal cortex (dPFC) of aged mice. The DNA methylation ratio increased in four CpG sites of abca7 promoter region and decreased in one CpG site of pyk2 promoter region, which were consistent with the altered expression of ABCA7 and PYK2. In conclusion, exposure to the real traffic environment impaired memory function and enhanced neuroinflammation of aged mice, which could be relevant to the alteration of ABCA7 and PYK2 gene expression. Our work provided a new and promising understanding of the pathological mechanisms of cognitive impairment caused by traffic-related air pollution. Overall design: The dorsolateral prefrontal cortex of aged mice exposed at campus and tunnel.