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

Abstract

In association with the mortality rate due to air pollution, vehicular emitted fine particles (PM 2.5) are a threat to public health. PM 2.5-induced in-vivo studies on environmental microorganisms can be used to assess the adverse impacts of PM 2.5 on human health. In the present study, the toxicity of traffic-related-air-pollutant (TRAP) PM 2.5 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 PM 2.5 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 PM 2.5 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 PM 2.5 were significantly shortened compared with those of untreated ones based on survival rate. The nematodes exposed PM 2.5 models not only posed potentially adverse health effects on human but also represented ecotoxic impacts on the ecosystem. In conclusion, heavy concentrations of TRAP PM 2.5 significantly and severely disrupted toxicological endpoints of neurology and reproduction to C. elegans. TRAP PM 2.5 significantly shortened the lifespan of the nematodes compared with the control. TRAP PM 2.5 might more severely influenced the specific toxic endpoints, such as lifespan and neurobehavira, in this in-vivo models compared with the reproductive endpoints.

The Impact of Background-Level Carboxylated Single-Walled Carbon Nanotubes (SWCNTs−COOH) on Induced Toxicity in Caenorhabditis elegans and Human Cells

“…Moreover, the C. elegans model lacks the animal ethics issues that are present with mammalian animal models. In our previous studies [36][37][38][39], shortened longevity, disruption of locomotion and reproduction, and the induction of an oxidative stress response were found after the nematodes were exposed to PM2.5, graphene oxide nanoparticles, and hydroxyl-and amine-functionalized silica nanoparticles. In C. elegans, exposure to multi-walled carbon nanotubes (MWCNTs) not only caused functional damage to both primary (e.g., intestine) and secondary (e.g., reproductive and neurons organs) targeted organs [40][41][42], they also induced translocation from the intestines to secondary targeted organs [40,41].…”

“…SWCNTs−COOH significantly induced ROS generation in THP-1 cells, as compared with the control group (Figure 7B). In our previous studies [36][37][38][39], the engineered nanomaterials (ENMs) of silica nanoparticles, including SiO 2 and NH 2 -SiO 2 , and graphene oxide as well as PM2.5 caused reproductive toxicity, a disruption of neurobehavior, and a shortened longevity for the nematodes. For the ambient PM2.5 level, both low levels of PM2.5 from rural areas and high levels of PM2.5 from heavy traffic emissions in urban areas induced the toxic effects on reproduction, delayed locomotion, and shortened the lifespan in wild-type C. elegans models [36,39].…”

Toxicity of Low-dose Graphene Oxide Nanoparticles in an in-vivo Wild Type of Caenorhabditis elegans Model

“…All physiological observations were done under a dissecting microscope (Olympus, SZX10, Waltham MA, USA). The experimental protocols in the nematode model followed those used in our previous study (Chung et al, 2019;Chung et al, 2020). The lethality, growth, reproduction, locomotion behavior examinations followed the protocols previously published, with minor modifications (Chung et al, 2019;Chung et al, 2020).…”

“…Three biological replicates were performed, and a total of 150 worms were evaluated. Several lifespan indicators (mean lifespan, day of 50 th percentile death, day of 75 th percentile death, day of 95 th percentile death, and day of all death) were evaluated by following the Chung's study (Chung et al, 2020).…”

Ecotoxicity testing of airborne particulate matter—comparison of sample preparation techniques for the Vibrio fischeri assay

“…Single-species tests have been used to study the chronic effects and mode of action of PM2.5 on the nematode Caenorhabditis elegans model species (Chung et al, 2019(Chung et al, , 2020.…”