At seeming safe concentrations, synergistic effects of PM 2.5 and formaldehyde co-exposure induces Alzheimer-like changes in mouse brain

// Xudong Liu 1, 2, * , Yuchao Zhang 2, * , Chen Luo 1 , Jun Kang 1 , Jinquan Li 1, 4 , Kun Wang 4 , Ping Ma 3 and Xu Yang 1 1 Laboratory of Environmental Biomedicine, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan, China 2 Department of Food science and Engineering, Moutai College, Renhuai, China 3 Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China 4 New York University School of Medicine, Tuxedo, New York, United States of America * These authors have contributed equally to this work Correspondence to: Xu Yang, email: yangxu@mail.ccnu.edu.cn Ping Ma, email: mping68@126.com Keywords: Alzheimer’s disease; air pollution; co-exposure; oxidative stress; inflammation Received: June 08, 2017      Accepted: August 26, 2017      Published: October 06, 2017 ABSTRACT Alzheimer’s disease (AD) is a serious, common, global disease, yet its etiology and pathogenesis are incompletely understood. Air pollution is a multi-pollutants co-exposure system, which may affect brain. The indoor environment is where exposure to both air particulate matter (<2.5 μm in diameter) (PM 2.5 ) and formaldehyde (FA) can occur simultaneously. Whether exposure to such a multi-pollutant (PM 2.5 plus FA) mixture contributes to the development of AD, and whether there is a difference between exposure to PM 2.5 or FA alone needs to be investigated. To determine the objective, C57BL/6J mice were exposed daily to PM 2.5 (0.193 mg/Kg/day), FA (0.155 mg/Kg/day) or multi-pullutants (0.193 mg/Kg/day PM 2.5 plus 0.155 mg/Kg/day FA) for one week. AD-like changes and upstream events were investigated after exposure. The results showed that exposure to PM 2.5 or FA alone in this study had little or no adverse effects on the mouse brain. However, some AD-like pathologies were detected after multi-pullutants co-exposure. This work suggested PM 2.5 plus FA co-exposure has more potential to induce AD-like pathologies than exposure alone. Oxidative stress and inflammation may be involved into the toxic mechanisms. Synergistic effects of co-exposure may induce the hygienic or safety standards of each pollutant not safe.