Formaldehyde cytotoxicity in three human cell types assessed in three different assays

Area of Science:

• Biomaterials Science
• Toxicology
• Cell Biology

Background:

• Current dental material preclinical screening relies on established cell lines.
• Formaldehyde, a potential dental material release product, necessitates accurate cytotoxicity assessment.
• Understanding cell line susceptibility is crucial for reliable in vitro testing.

Purpose of the Study:

• To compare the cytotoxicity of formaldehyde on human dental pulp fibroblasts (HPF), human buccal epithelial cells (HBE), and HeLa cells.
• To evaluate the influence of different cytotoxicity assays (BrdU, Neutral Red, MTT) on results.
• To determine the most sensitive cell model for dental material cytotoxicity testing.

Main Methods:

• Exposed HPF, HBE, and HeLa cells to varying formaldehyde concentrations.
• Assessed cytotoxicity using BrdU incorporation, Neutral Red uptake, and MTT assays.
• Calculated dose-response relationships and TC(50) values for each cell type and assay.

Main Results:

• HPF and HBE cells showed significantly lower TC(50) values than HeLa cells in Neutral Red and BrdU assays.
• MTT assay yielded no significant differences in TC(50) between cell types.
• Neutral Red assay indicated higher sensitivity in HPF and HBE cells compared to the BrdU assay.

Conclusions:

• Cytotoxicity data is influenced by the chosen cell model and assay method.
• Human target tissue cells (HPF, HBE) are more sensitive to formaldehyde than HeLa cells.
• Results suggest using human-derived cells for more accurate dental material cytotoxicity screening.