Inhalation toxicity of polystyrene micro(nano)plastics using modified OECD TG 412

Recently, there have been reports that many microplastics are found in the air, which has raised concerns about their toxicity. To date, however, only limited research has investigated the effects of micro(nano) plastics on human health, and even less the potential for inhalation toxicity. To fill this research gap, we investigated the potential inhalation toxicity of micro(nano)plastics using a modified OECD Guideline for Testing of Chemicals No. 412 '28-Day (subacute) inhalation toxicity study' using a whole-body inhalation system. Sprague-Dawley rats were exposed to three different exposure concentrations of polystyrene micro(nano)plastics (PSMPs), as well as control, for 14 days of inhalation exposure. After 14 days, alterations were observed on sevral endpoints in physiological, serum biochemical, hematological, and respiratory function markers measured on the samples exposed to PSMPs. However, no concentrationresponse relationships were observed, suggesting that these effects may not be definitively linked to exposure of PSMPs. On the other hand, the expression of inflammatory proteins (TGF-beta and TNIF-alpha) increased in the lung tissue in an exposure concentration-dependent manner. The overall results indicate that 14-day inhalation exposure of PSMPs to rats has a more pronounced effect at the molecular level than at the organismal one. These results suggest that if the exposure sustained, alterations at the molecular level may lead to subsequent alterations at the higher levels, and consequently, the health risks of inhalation exposed micro(nano)plastics should not be neglected. (C) 2020 Published by Elsevier Ltd.

Automated summary

Through a 14-day inhalation exposure experiment on rats, significant alterations were observed on various physiological, hematological, and respiratory function markers under exposure to micro(nano)plastics. Additionally, an exposure concentration-dependent increase in inflammatory proteins in lung tissue was found. These results suggest that the health risks of inhalation-exposed micro(nano)plastics should not be overlooked, as molecular level alterations may lead to subsequent effects at higher levels.