Evaluating the Relationship Between Nano and Microplastic Size and Composition in Pulmonary Genotoxicity and Inflammation In Vitro

Details

• Personal Author:
  Fraser, Kelly ; Aldinger, Jeffrey A. ; Roberts, Jennifer R.
• Description:
  Background and Purpose: Nano and Microplastics are an environmental and occupational health concern due to the rapidly growing industry predicted to result in the production of over 34 billion tons of plastic by 2050. Recently, studies have found increasing concentrations of micro and nano sized plastic particles in the environment, including in the ambient air, food chain, and water supplies. Additionally, the inhalation of micro and nano plastics as an occupational concern has been raised, though little information of the extent of these exposures has been uncovered. Few studies have been able to determine occupational exposure levels due to limitations in methods and sampling techniques, though concerns for exposure in the textiles, fiber manufacturing, flocking, waste management, and more recently, additive manufacturing industries, have been noted. Several studies have linked microplastics to inflammation, cell injury, genotoxicity, and other mechanisms that may result in adverse health outcomes such as respiratory and allergic diseases. The lack of thorough data correlating microplastic particle size, surface reactivity, chemical composition, and other physicochemical characteristics to these toxicity outcomes has resulted in a significant knowledge gap. The current study aimed to investigate two plastic nanoparticles, polystyrene (PS) and polymethyl methacrylate (PMMA) at two different particle sizes (15 nm and 1000nm diameters) for pulmonary genotoxicity and inflammation in vitro. Methods: Two sizes of two plastic microspheres, PS and PMMA, were used in the current study. These particles were fluorescently tagged (488/560) and were either 15 nm or 1000 nm in diameter. Human bronchiolar epithelial cells (BEAS-2B) were used to investigate the genotoxicity of the microplastics, while differentiated human monocytes (THP-1s) were used to assess inflammation. In both cell lines, cell viability and proliferation were assessed after 24- hour exposure to nano and microplastics at doses ranging 0-500 µg/ml using WST-1 and Alamar Blue in addition to lactate dehydrogenase (LDH) in THP-1 cells. DNA damage, cell cycle disruption, and oxidative stress were assessed in BEAS-2B cells while caspase-1 activity and IL-1β release was assessed in THP-1 cells. Results: Cytotoxicity occurred at lower doses after exposure to 15 nm particles when compared to their larger diameter counterparts. The 1000 nm diameter PS particle had minimal effect on cell viability, even at 500 µg/ml, while the 1000 nm diameter PMMA particle significantly reduced viability at approximately 300 µg/ml in the Alamar Blue assay. No significant changes in DNA damage or cell cycle occurred at 6.25 or 25 µg/ml for either particle; however, all materials and sizes induced varying degrees of oxidative stress with the 1000 nm PS particle inducing a more significant increase at the high dose. Each particle increased Caspase-1 activity at 6 hours beginning at the lower doses. Additionally, lower doses of 1000 nm PS increased IL-1B release at 24 hours of exposure. Conclusions: Overall, minimal to no change in cell viability occurs at doses lower than 180 µg/ml for both particles and sizes; however, the larger diameter particles were not as cytotoxic as the smaller particles at a given dose. Although there was minimal genotoxicity following exposure to any of the particles, oxidative stress was induced by all materials and inflammation occurred with all particles. These findings varied with chemical composition, size, and dose. Overall, PS1000 was the most toxic of the particles at the 25 and 6.25 µg/ml doses, though the smaller diameter particles affected cell viability and proliferation at lower doses compared to the larger diameter particles, while PMMA1000 was the least toxic. This data suggests that both particle size and chemical composition are prominent determinants of micro and nano plastic toxicity. Description provided by NIOSH
• Subjects:
  • DNA Damage
  • Microplastics
  • Occupational Health
  • Oxidative Stress
  • Particulate Matter
  • Respiratory System
  • Safety
• Keywords:
  • Nanoplastics; Particle size; Pulmonary effects; Genotoxicity; DNA damage; Oxidative stress
• Source:
  Toxicologist 2025 Mar; 204(S1):465-466
• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  Philadelphia Region OSHA ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  3 pdf pages
• Volume:
  204
• NIOSHTIC Number:
  nn:20071584
• Federal Fiscal Year:
  2025
• Peer Reviewed:
  False
• Download URL:
  https://stacks.cdc.gov/view/cdc/259359/cdc_259359_DS1.pdf
• File Type:
  [PDF - 297.31 KB]
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:bf3b6636cc8ac189c21214011b52643a44c01accc0bd0dca1915bec6c55ef21d40e2ec10615979530b51a2d15a58ff43755ffb3da1c171fde4b032e87380696b