Leveraging a TRPV1-overexpressing cell model: an integrated testing strategy for UV filter-induced ocular irritation

Eye discomfort is a common issue for consumers using sunscreen products. While UV filters are suspected of being the main cause, no clear scientific evidence has been found to support this hypothesis. This research aims to develop a scientifically effective eye irritation screening method to provide a scientific explanation for the eye discomfort caused by UV filters.

In order to assess the ocular irritation of two UV filters, Octocrylene (OCT) and Ethylhexyl methoxycinnamate (OMC), a combination of in silico and in vitro methods was employed. In silico prediction was conducted using seven computational ADMET prediction models (e.g. AdmetSAR 3.0, ADMETlab 2.0). The in vitro experimental validation included Bovine Corneal Opacity and Permeability (BCOP) and Short Time Exposure (STE) assays, and TRPV1 ion channel activation was probed using TRPV1-overexpressing rabbit corneal epithelial cells (TRPV1-OE SIRC cells).

Different in silico toxicology prediction models did not yield consistent results regarding the eye irritation potential of the two UV filters. The results of the BCOP and STE tests showed that both UV filters were nonirritating. Detection of TRPV1 channel activation indicated that OCT can induce Ca²⁺ influx in cells, resulting in ocular discomfort, while OMC did not.

These results indicated that this in vitro screening method based on the activation of the TRPV1 channel is more sensitive in detecting stinging sensations in the eyes. This mechanism may provide a possible explanation for UV filter-induced eye discomfort and has potential for screening other cosmetic ingredients that cause such discomfort without irritation.