Local lymph node assay (LLNA): comparison of different protocols by testing skin-sensitizing epoxy resin system...

Area of Science:

• Toxicology
• Dermatology
• Chemical Safety

Background:

• Epoxy resins are widely used industrial chemicals.
• Assessing their skin sensitization potential is crucial for occupational safety.
• Standardized testing methods are needed to accurately evaluate sensitizing potency.

Purpose of the Study:

• To evaluate the skin-sensitizing potency of thirteen epoxy resin system components using the Local Lymph Node Assay (LLNA).
• To compare the impact of different vehicles on sensitization induction.
• To discuss challenges in comparing results from various LLNA protocols.

Main Methods:

• Thirteen epoxy resin components were tested in the LLNA.
• Lymph node stimulation was quantified by [3H]-thymidine incorporation and cell counts.
• Tests were conducted using acetone as a vehicle, and then compared with an acetone/olive oil (4:1) vehicle for selected items.

Main Results:

• All tested epoxy resin components exhibited skin-sensitizing potential, ranging from moderate to strong.
• Using an acetone/olive oil vehicle resulted in lower estimated concentrations for sensitization induction compared to acetone alone.
• Adjusting reference stimulation indices allowed for equivalent figures using both [3H]-thymidine incorporation and cell counts.

Conclusions:

• Epoxy resin components possess significant skin-sensitizing properties.
• The choice of vehicle in LLNA significantly influences the assessment of sensitization potency.
• Standardization of LLNA protocols and vehicle selection is essential for reliable risk assessment of epoxy resins.