Assessing ocular irritation potential using a modified ex vivo rabbit eye test.
James V Jester1, Larry Lam, Andrew Wahlert
1Gavin Herbert Eye Institute and Department of Biomedical Engineering, University of California, Irvine, Orange, 92868, USA. jjester@uci.edu
Cutaneous and Ocular Toxicology
|June 12, 2009
Summary
Para-toluene sulfonic acid (pTSA) shows minimal ocular irritation at low concentrations. Higher concentrations (10%+) exhibit mild to slight irritancy, comparable to acetic acid, suggesting a useful ex vivo eye test model.
Area of Science:
- Toxicology
- Ocular Irritation Assays
- In Vitro Testing
Background:
- Para-toluene sulfonic acid (pTSA) is an environmental contaminant requiring ocular irritancy assessment.
- Traditional Draize rabbit eye tests face ethical and practical challenges.
- Cytotoxicity assays offer a mechanistic correlate for ocular irritation.
Purpose of the Study:
- To evaluate the ocular irritancy potential of para-toluene sulfonic acid (pTSA).
- To compare pTSA's irritancy with known irritants like sodium dodecyl sulfate (SDS) and acetic acid (AA).
- To validate a modified ex vivo rabbit eye test using a live/dead cytotoxicity assay.
Main Methods:
- Utilized ex vivo rabbit corneas obtained from an abattoir.
- Exposed corneas to varying concentrations of pTSA, SDS, and AA.
- Quantified cell death using a calcein AM/ethidium homodimer live/dead assay and laser scanning confocal microscopy.
Main Results:
- Low concentrations (1 ppm, 1%) of pTSA showed no significant difference in cytotoxicity compared to controls.
- Higher concentrations (10%, 50%) of pTSA induced significant cytotoxicity (p < .0001).
- Cytotoxicity from 10% pTSA was comparable to 10% acetic acid.
Conclusions:
- pTSA is an innocuous irritant at environmentally relevant concentrations.
- Concentrations of 10% and above classify pTSA as a slight to mild ocular irritant.
- The modified ex vivo rabbit eye test with live/dead assay is a promising model for ocular irritation testing.
