Related Experiment Video
Updated: Jun 24, 2026
Evaluating Therapeutic and Chemical Toxicity Using Organ-Cultured Porcine Corneas and Epithelial Wound Healing
Published on: January 10, 2025
Do multipurpose solutions damage porcine corneal epithelial cells?
Camus Kar Man Choy1, Pauline Cho, Maureen V Boost
1School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, PR China.
Purpose:
To determine and compare the cytotoxic effects on porcine corneal epithelial cells of commercially available multipurpose solutions (MPS) using fluorescein staining and flow cytometry (FCM).
Methods:
Effects of exposure time of 10 s to 10 min of MPS containing polyquaternium-1 (MPS-A), polyaminopropyl biguanide (MPS-B), and polyhexanide (MPS-C), on porcine corneal epithelial cells were determined. Cell viability and membrane integrity were assessed by Annexin V-FITC/7-AAD staining and FCM. In further trials, whole corneas were immersed in MPS and control (buffered saline), and corneal fluorescein staining assessed before FCM analysis.
Results:
Significantly higher percentages of 7-AAD-stained cells (early necrosis) were observed at all exposure times for MPS-A than for other solutions and control (p < 0.05). Exposure time in MPS-A and 7-AAD-stained cell proportions showed significant correlation (r = 0.9957; p < 0.0001). Significantly more cells dual-stained with Annexin V-FITC/7-AAD (late necrosis) after 5 min MPS-A exposure (11.8 +/- 1.1%), compared with 1.2 +/- 0.9% (MPS-B), 0.9 +/- 0.5% (MPS-C), and 1.8 +/- 0.2% (control). However, only 10 min exposure resulted in significant increases in fluorescein grades (p < 0.001), with median grade 0.75 for MPS-A, and 0.50 for the other MPS.
Conclusions:
MPS exposure, especially MPS-A, affected the viability and integrity of porcine corneal epithelial cells. Furthermore, our results confirmed that fluorescein staining correlates poorly with cytotoxicity. As fluorescein staining lacks sensitivity to determine cytotoxic effects of ophthalmic solutions, more objective and sensitive assessment methods such as differential staining and FCM should be developed.
Insights
Multipurpose solutions (MPS) containing polyquaternium-1 (MPS-A) showed significant cytotoxicity to porcine corneal cells, unlike other MPS. Fluorescein staining is not a sensitive method for assessing ophthalmic solution cytotoxicity.
Area of Science:
- Ophthalmology
- Cell Biology
- Toxicology
Background:
- Ophthalmic solutions, including multipurpose solutions (MPS), are widely used for contact lens care.
- Assessing the cytotoxic effects of MPS on ocular surface cells is crucial for patient safety.
- Previous methods for evaluating cytotoxicity may lack sensitivity.
Purpose of the Study:
- To compare the cytotoxic effects of commercially available MPS on porcine corneal epithelial cells.
- To evaluate the efficacy of fluorescein staining versus flow cytometry (FCM) in detecting cytotoxicity.
Main Methods:
- Porcine corneal epithelial cells were exposed to MPS containing polyquaternium-1 (MPS-A), polyaminopropyl biguanide (MPS-B), and polyhexanide (MPS-C) for varying durations.
- Cell viability and membrane integrity were assessed using Annexin V-FITC/7-AAD staining and FCM.
- Corneal fluorescein staining was performed on whole corneas immersed in MPS and controls.
Main Results:
- MPS-A demonstrated significantly higher cytotoxicity, indicated by increased 7-AAD staining (early necrosis) and Annexin V-FITC/7-AAD staining (late necrosis), compared to MPS-B, MPS-C, and controls.
- Cytotoxicity of MPS-A showed a strong positive correlation with exposure time.
- Fluorescein staining showed poor correlation with cytotoxicity and lacked sensitivity in detecting early cellular damage.
Conclusions:
- MPS, particularly MPS-A, exerts significant cytotoxic effects on porcine corneal epithelial cells.
- Fluorescein staining is an insensitive method for assessing the cytotoxic potential of ophthalmic solutions.
- Differential staining and FCM are more reliable and sensitive methods for evaluating the cytotoxicity of ophthalmic solutions.
