Micronucleus Formation in Primary Oropharyngeal Epithelial Cells Reveals Mutagenicity of Cement Dusts

Abstract

Background/aim: Epidemiological studies showed an increased risk of developing laryngeal head and neck squamous cell carcinoma (HNSCC) for employees working in the construction business. This suggested a causal link between exposure to cement particles and development of HNSCC but data were missing.

Materials and methods: We established an Organisation for Economic Co-operation and Development (OECD) guideline 487-conform micronucleus assay (MNA) using oropharyngeal mucosa-derived primary epithelial cells (OPCs) ex vivo. OPCs from healthy mucosa of 52 donors were cultured in vitro and incubated with serial concentrations of two common cement particles. Mitomycin C was used as a soluble positive control, and TiO₂ and DQ12 were used as negative and positive particle controls. Bi-nucleated cells were counted and the mitotic index (MI) was determined. Subsequently, micronuclei-containing bi-nucleated cells (MN+) were counted.

Results: Cement particles, in concentrations not significantly reducing ex vivo proliferation according to mitotic index, dose-dependently increased micronuclei formation.

Conclusion: Through the establishment of an OECD guideline 487 conform MNA, we demonstrate the mutagenic effects of cement on human OPCs.

Keywords: Micronucleus assay; cement dust; oropharyngeal mucosa-derived primary epithelial cells.