Investigating the chronic impacts of urban air quality on the brain using wild grey squirrels as sentinels for urban wildlife

空气污染是全球公认的对人类健康最致命的危害之一。城市空气污染具有独特的物理化学性质，含有危险程度的金属微粒，主要来自与交通有关的来源。对人类和伴侣动物的流行病学研究表明，暴露于高水平的空气污染物与癌症、心血管和呼吸系统疾病有关，最近还与认知发育不良和痴呆症发病率增加有关。尽管有强有力的相关证据表明空气污染对人类健康和认知的影响，但对其他城市动物影响的经验证据非常有限。此外，对所观察到的认知能力下降的致病机制的理解有限，尽管有人提出空气中的金属颗粒可能通过嗅觉神经元的摄取进入大脑。这项研究旨在使用东灰松鼠（Sciurus carolinensis），一种在英国各地发现的入侵啮齿动物，并作为英国控制计划的一部分被扑杀，以阐明与大脑中金属空气污染物吸收相关的机制。这将使我能够测量进入大脑的金属污染暴露途径，并量化金属颗粒的金属积累和空间分布。此外，委员会认为，我将通过检查这些个体的压力和表观遗传变化的标志物以及疾病发展的迹象来测量对金属污染暴露的反应，方法是通过组织病理学评估大脑炎症和神经退行性变的水平，以及生活在金属空气污染梯度的灰松鼠种群的认知差异，从高度污染的市中心种群到生活在农村林地的种群，城市空气污染水平较低。交通暴露。

Air pollution is recognised globally as one of the deadliest hazards to human health. Urban air pollution has a unique physiochemistry and contains hazardous levels of metal particulates originating mainly from traffic-related sources. Epidemiological studies on humans and companion animals have associated exposure to high levels of air pollutants with cancer, cardiovascular and respiratory diseases and more recently, poor cognitive development and increased incidence of dementia. Despite strong correlative evidence of the impact of air pollution on human health and cognition, there is very limited empirical evidence for impacts on other urban animals. Furthermore, there is limited understanding of the causative mechanisms underlying the observed cognitive decline, though it has been proposed that airborne metal particles may access the brain via uptake by olfactory neurons. This studentship aims to use the eastern grey squirrel (Sciurus carolinensis), an invasive rodent found throughout the UK and culled as part of UK control programs, to elucidate the mechanisms associated with the uptake of metal air pollutants in the brain. This will allow me to measure metal-pollution exposure pathways into the brain and quantify metal accumulation and spatial distribution of metal particles. Furthermore, I will measure response to metal pollution exposure by examining markers of stress and epigenetic changes in these individuals as well as signs of disease development by assessing levels of brain inflammation and neurodegeneration through histopathology and differences in cognition in populations of grey squirrels living at a gradient of metal air pollution from highly polluted inner-city populations to those living in rural woodlands with lower urban-traffic exposures.