Mouse pulmonary response following solid surface composite dust inhalation

Purpose: Pulmonary exposure to emissions from manipulating solid surface composite (SSC) materials has been associated with adverse health effects in humans and laboratory animals. Previous in vitro and in vivo investigations of SSC toxicity have been limited by particle delivery methods that do not fully recapitulate the workplace environment. This study sought to determine the acute SSC-induced pulmonary responses via whole-body inhalation exposure. Materials and Methods: A chamber for dust particle generation and an exposure system for characterization and animal exposures was constructed. The system successfully generated SSC at a concentration of 19.9 ± 1.5 mg/m³. The aerosol count median aerodynamic diameter was 820 nm. First, C57BL/6 mice were exposed to SSC particles for 4 h (n = 6) or filtered air control followed by euthanasia either immediately or 24 h post-exposure. Lungs were analyzed for aluminum (Al) content using inductively coupled plasma atomic emission spectroscopy (ICP-AES) which measured a lung deposition of 19.13 ± 5.03 µg/g elemental Al, or approximately 64 µg/g SSC dust. Second, a group of mice (n = 9) was exposed to SSC particles at 20 mg/m³ for 4 days, 4 h/day to assess the acute and sub-chronic pulmonary effects of SSC inhalation. Animals were euthanized at 1- and 56-days post-exposure. Results: Total estimated pulmonary deposition for these animals was 49.2 µg SSC dust/animal. No histopathologic changes were observed at any post-exposure time point; however, BALF total protein was increased at 1-day post-exposure. Conclusions: We conclude that exposure to dust from cutting SSC at this dose and post-exposure durations induces mild, transient inflammation.