Magnetic resonance imaging investigations reveal that PM2.5 exposure triggers visual dysfunction in mice

Linying Guo; He Wang; Ji Zhou; Weijun Tang; Rong Wang; Zebin Xiao; Lingjie Wu; Jie Wang; Liping Li; Yuan Lei; Xinghuai Sun; Zuohua Tang

doi:10.1016/j.ecoenv.2021.112866

Magnetic resonance imaging investigations reveal that PM_2.5 exposure triggers visual dysfunction in mice

Ecotoxicol Environ Saf. 2021 Dec 20:227:112866. doi: 10.1016/j.ecoenv.2021.112866. Epub 2021 Oct 8.

Authors

Linying Guo¹, He Wang², Ji Zhou³, Weijun Tang⁴, Rong Wang⁴, Zebin Xiao⁵, Lingjie Wu⁶, Jie Wang⁷, Liping Li⁸, Yuan Lei⁹, Xinghuai Sun¹⁰, Zuohua Tang¹¹

Affiliations

¹ Department of Radiology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China.
² Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, China.
³ Shanghai Key Laboratory of Meteorology and Health, Shanghai Meteorological Bureau, Shanghai 200030, China; Shanghai Typhoon Institute, CMA, Shanghai 200030, China; Department of Atmospheric and Oceanic Sciences & Institute of Atmospheric Sciences, Fudan University, Shanghai 200031, China.
⁴ Department of Radiology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200040, China.
⁵ Department of Radiology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China; Department of Biomedical Sciences, University of Pennsylvania, 22, Philadelphia, PA 19104, United States.
⁶ Department of Ear, Nose & Throat, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China.
⁷ Department of Radiotherapy, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China.
⁸ Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China.
⁹ Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China; NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China. Electronic address: lilian0167@hotmail.com.
¹⁰ Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China; NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China. Electronic address: xhsun@shmu.edu.cn.
¹¹ Department of Radiology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China. Electronic address: tzh518sunny@163.com.

PMID: 34634599
DOI: 10.1016/j.ecoenv.2021.112866

Abstract

Objectives: To investigate how PM_2.5 exposure affects the microstructure, metabolites or functions of the visual system.

Methods: C57BL/6J mice were randomly assigned to groups exposed to the filtered air (the control group) or the concentrated ambient PM_2.5 (the PM_2.5 group). Visual evoked potentials (VEP), electroretinograms (ERG), diffusion tensor imaging (DTI), proton magnetic resonance spectroscopy (¹H-MRS) and resting-state functional MRI (rsfMRI) were performed. Parameters were obtained and compared between the two groups, including latencies and amplitudes of the P1 wave, N1 wave and P2 wave from VEP, latencies and amplitudes of the a wave and b wave from ERG, fractional anisotropy (FA), mean diffusion (MD), axial diffusivity (AD) and radial diffusivity (RD) from DTI, visual cortex (VC) metabolites from ¹H-MRS, and regional homogeneity (ReHo) from rsfMRI.

Results: Compared with the values of the control group, the PM_2.5 group showed a prolonged N1 latency (43.11 ± 7.94 ms vs. 38.75 ± 4.60 ms) and lowered P1 amplitude (5.62 ± 4.38 μV vs. 8.56 ± 5.92 μV) on VEP (all p < 0.05). On ERG, the amplitude of the a wave was lowered (- 91.39 ± 56.29 μV vs. - 138.68 ± 89.05 μV), the amplitude of the b wave was lowered (194.38 ± 126.27 μV vs. 284.72 ± 170.99 μV), and the latency of the b wave was prolonged (37.78 ± 10.72 ms vs. 33.01 ± 4.34 ms) than the values of the control group (all p < 0.05). DTI indicated FA increase in the bilateral piriform cortex (Pir), FA decrease in the bilateral somatosensory cortex (S) and the bilateral striatum (Stri), AD decrease in the bilateral VC, the right S and the bilateral Pir, MD decrease in the bilateral Pir, and RD decrease in the bilateral Pir in the PM_2.5 mice (all p < 0.05, Alphasim corrected). ¹H-MRS showed Glutamate (Glu) increase and Phosphocholine (PCh) increase in the VC of the PM_2.5 group than those of the control group (PCh 1.63 ± 0.25 vs. 1.50 ± 0.25; PCh/total creatine(tCr) 0.19 ± 0.03 vs. 0.18 ± 0.03; Glu 10.46 ± 1.50 vs. 9.60 ± 1.19; Glu/tcr 1.23 ± 0.11 vs. 1.12 ± 0.11) (all p < 0.05). rsfMRI showed higher ReHo in the PM_2.5 mice in the left superior colliculus, the left motor cortex, the hippocampus, the periaqueductal gray and the right mesencephalic reticular formation (all p < 0.01, AlphaSim corrected).

Conclusions: This study revealed that PM_2.5 exposure triggered visual dysfunction, and altered microstructure, metabolite and function in the retina and visual brain areas along the visual system.

Keywords: Diffusion tensor imaging; PM(2.5) exposure; Proton magnetic resonance spectroscopy; Resting state functional MRI; Visual electrophysiology.

MeSH terms

Animals
Diffusion Tensor Imaging*
Evoked Potentials, Visual*
Magnetic Resonance Imaging
Mice
Mice, Inbred C57BL
Particulate Matter / toxicity

Substances

Particulate Matter