Optimizing photopollution assessment: Insights from a reconstructed human epidermis model

Area of Science:

• Dermatology and toxicology
• In vitro skin models
• Environmental exposure studies

Background:

• Reconstructed Human Epidermis (RHE) models provide ethical, in vitro alternatives for cosmetic safety testing.
• RHE models are crucial for studying skin responses to stressors like UV radiation and air pollution.
• Oxidative stress and inflammation are key responses to environmental skin stressors.

Purpose of the Study:

• To optimize a photopollution model using SkinEthic™ RHE for evaluating oxidative stress biomarkers.
• To assess antioxidant protection under combined UVA and airborne particulate matter (PM) exposure.
• To investigate the synergistic effects of PM2.5 and UVA on RHE models.

Main Methods:

• RHE models were exposed to nebulized PM2.5 followed by UVA radiation.
• Reactive oxygen species (ROS) were quantified using the DCFH2-DA probe.
• Gene expression (NRF2, IL-18) and cytokine secretion (IL-18) were assessed at 4h and 24h post-exposure.

Main Results:

• Combined PM2.5 and UVA exposure induced a synergistic 95% increase in intracellular ROS.
• UVA exposure alone caused a 45% rise in ROS; PM2.5 alone did not significantly increase ROS.
• Co-exposure significantly upregulated NRF2 and IL-18 gene expression and induced IL-18 secretion, with IL-18 being the most responsive inflammatory marker.

Conclusions:

• The developed RHE exposure model effectively simulates photopollution-induced oxidative stress.
• The model demonstrates predictive capacity for evaluating oxidative stress biomarkers and inflammatory responses.
• This RHE model supports further research into skin-environment interactions and potential protective strategies.