Toxic Assessment of Heavily Traffic-related Fine Particulate Matter Using an in-vivo Wild-type Caenorhabditis elegans Model

Meng-Ching Chung,Japheth L Avelino,Sheng-Lun Lin,Ming-Hsien Tsai,Lemmuel L Tayo,Chih-Chung Lin,Sen-Ting Huang,Kuo-Lin Huang,Wan Nurdiyana Wan Mansor,Ching-Kai Su

doi:10.4209/aaqr.2020.05.0192

Abstract

ABSTRACT In association with the mortality rate due to air pollution, vehicular emitted fine particles (PM2.5) are a threat to public health. PM2.5-induced in-vivo studies on environmental microorganisms can be used to assess the adverse impacts of PM2.5 on human health. In the present study, the toxicity of traffic-related-air-pollutant (TRAP) PM2.5 was evaluated in the animal model Caenorhabditis elegans (C. elegans) using different toxicological endpoints such as lethality, survivability (lifespan), behavioral (head thrashing and body bending), and reproduction (brood size). The TRAP PM2.5 sample were collected in Taichung City, Taiwan from Mar 24 to April 15 in 2018. Of these 23 day samples, three samples (Days A, B, and C) were randomly selected. The results showed that no immediate lethality was observed after acute (24 h) exposure of the nematodes. On the other hand, sublethal endpoints of reproduction exhibited statistically significant dose-dependent reduction, although Day A and Day C did not decrease the egg-laying capability of the worms. For the neurological toxicity, it is inferred that the higher the PM2.5 concentrations, the more the adverse effects of neurobehavior (head trashing and body bending) it poses on the C. elegans. The lifespans of nematodes exposed to heavily TRAP PM2.5 were significantly shortened compared with those of untreated ones based on survival rate. The nematodes exposed PM2.5 models not only posed potentially adverse health effects on human but also represented ecotoxic impacts on the ecosystem. In conclusion, heavy concentrations of TRAP PM2.5 significantly and severely disrupted toxicological endpoints of neurology and reproduction to C. elegans. TRAP PM2.5 significantly shortened the lifespan of the nematodes compared with the control. TRAP PM2.5 might more severely influenced the specific toxic endpoints, such as lifespan and neurobehavira, in this in-vivo models compared with the reproductive endpoints.

Highlights

Ambient and indoor air pollution, the most important environmental risk to health, contributed 7 million deaths each year in the past decade (WHO, 2016)
The increasing epidemiological studies indicate that cardiopulmonary morbidity due to PM2.5 exposure play a part in the development of diabetes mellitus and adverse birth outcomes (Hu, 2009; Crouse et al, 2012; Kloog et al, 2012; Chen et al, 2013; Burnett et al, 2014; Zanobetti et al, 2014)
PM2.5 and PM10 were highly correlated because they are particulate phase emitted from the TRAP pollution (Fig. 1)

Summary

Introduction

Ambient and indoor air pollution, the most important environmental risk to health, contributed 7 million deaths each year in the past decade (WHO, 2016). Reports have shown that worldwide exposure to outdoor PM2.5 contributed to 4.1 million deaths connected with heart disease and stroke, lung cancer, chronic lung disease, and respiratory infections (Orru et al, 2011; HEI, 2018; Li et al, 2018; Hayes et al, 2019). PM2.5 is accountable for a substantially larger number of attributable deaths than other more well-known life behavioral risk factors such as physical inactivity, alcohol use, and high sodium intake, and it is equivalent to the attributable deaths caused by high cholesterol and high body mass index (HEI, 2018)

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