Mouse pulmonary response to dust from sawing Corian®, a solid-surface composite material

ABSTRACT

Corian®, a solid-surface composite (SSC), is composed of alumina trihydrate and acrylic polymer. The aim of the present study was to examine the pulmonary toxicity attributed to exposure to SSC sawing dust. Male mice were exposed to either phosphate buffer saline (PBS, control), 62.5, 125, 250, 500, or 1000 µg of SSC dust, or 1000 µg silica (positive control) via oropharyngeal aspiration. Body weights were measured for the duration of the study. Bronchoalveolar lavage fluid (BALF) and tissues were collected for analysis at 1 and 14 days post-exposure. Enhanced-darkfield and histopathologic analysis was performed to assess particle distribution and inflammatory responses. BALF cells and inflammatory cytokines were measured. The geometric mean diameter of SSC sawing dust following suspension in PBS was 1.25 µm. BALF analysis indicated that lactate dehydrogenase (LDH) activity, inflammatory cells, and pro-inflammatory cytokines were significantly elevated in the 500 and 1000 µg SSC exposure groups at days 1 and 14, suggesting that exposure to these concentrations of SSC induced inflammatory responses, in some cases to a greater degree than the silica positive control. Histopathology indicated the presence of acute alveolitis at all doses at day 1, which was largely resolved by day 14. Alveolar particle deposition and granulomatous mass formation were observed in all exposure groups at day 14. The SSC particles were poorly cleared, with 81% remaining at the end of the observation period. These findings demonstrate that SSC sawing dust exposure induces pulmonary inflammation and damage that warrants further investigation.

Abbreviations: ANOVA: Analysis of Variance; ATH: Alumina Trihydrate; BALF: Bronchoalveolar Lavage Fluid; D_pg: Geometric Mean Diameter; FE-SEM: Field Emission Scanning Electron Microscopy; IACUC: Institutional Animal Care and Use Committee; IFN-γ: Interferon Gamma; IL-1 Β: Interleukin-1 Beta; IL-10: Interleukin-10; IL-12: Interleukin-12; IL-2: Interleukin-2; IL-4: Interleukin-4; IL-5: Interleukin-5; IL-6: Interleukin-6; KC/GRO: Neutrophil-Activating Protein 3; MMAD: Mass Median Aerodynamic Diameter; PBS: Phosphate-Buffered Saline; PEL: Permissible Exposure Limit; PM: Polymorphonuclear Leukocytes; PNOR: Particles Not Otherwise Regulated; SEM/EDX: Scanning Electron Microscope/Energy-Dispersive X-Ray; SSA: Specific Surface Area; SSC: Solid Surface Composite; TNFα: Tumor Necrosis Factor-Alpha; VOC: Volatile Organic Compounds; σ_g: Geometric Standard Deviation.

KEYWORDS:

• Particle toxicity
• composites
• pulmonary injury
• airborne particles
• risk assessment

Authors’ contributions

CQ, YQ, and JDS contributed to the study design and conception. JDS and JS performed the toxicological experiments. WKM performed particle size distribution experiments, prepared figures and drafted the manuscript. CQ performed particle generation and contributed to the manuscript. LAB performed tissue collection for histological examination. MSO performed histopathology and contributed to the manuscript. KS performed statistical analysis. RRM performed enhanced dark-field image analysis and contributed to the manuscript. SF performed electron microscopy. JS assisted with ABS, AKK, and LNB performed material characterization experiments and contributed to the manuscript.

Competing interests

The authors declare that they have no competing interests with respect to the research, authorship, and/or publication of this article.

Disclaimer

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention.

Ethics approval

All procedures in the study comply with the ethical standards set forth by the Animal Welfare Act (enforced by the United States Department of Agriculture) and the Office of Laboratory Animal Welfare (OLAW). The studies were approved by the NIOSH Health Effects Laboratory Division (HELD) Institutional Animal Care and Use Committee within the Center for Disease Control.

Supplemental material

Supplemental data can be accessed here.

Additional information

Funding

Internal NIOSH funding.