Corneal epithelial cells viability

Summary: A way to assess the acute and chronic toxic or protective effects of a novel drug candidate or topical formulation.

Model Description

The corneal epithelium provides an important barrier against fluid loss and protection from the external environment. Disease or injury to the corneal epithelium through viral infection, penetration of chemicals applied topically, or exposure to toxic radiation results in toxicity, irritation, or inflammation. Such reactions in the cornea can cause loss of visual acuity. 

Acute and chronic toxic or protective effects of the novel drug candidates or topical formulations can be evaluated using cultured human corneal epithelial cells, HCE-T (Araki-Sasaki et al., 1995).  

Cells or tissues Human corneal epithelial cells (HCE-T, RIKEN, Japan) 
Viability assessment HCE-T cells are grown on 96-well plates. The cells can be exposed to testing molecules or formulations for a period from a few minutes to 3-4 days. Cytotoxicity is measured using resazurin reduction assay (Nociari et al., 1998). The resazurin assay offers a simple, rapid, and sensitive measurement for the viability of HCE-T cells (Hakkarainen et al., 2016). A cell permeable redox indicator resazurin (7-Hydroxy-3H-phenoxazin-3-one-10-oxide) is used to measure oxidation-reduction reactions in viable cells. The non-fluorescent resazurin is irreversibly reduced by metabolically active cells to highly fluorescent metabolite resorufin (7-Hydroxy-3H-phenoxazin-3-one). Resorufin formation is measured by using Cytation 3 multi-mode reader (BioTek Instruments, Winooski, VT, USA).  The quantity of resorufin produced is proportional to the number of viable cells. 
Positive control Benzalkonium chloride (BAC) 
Read-outs 1. Cell viability (%)
2. IC50 value (50% cell viability) for positive control
3. IC50 value is calculated for study compound if applicable

Outcomes and Read-Outs 

Fig. 1. Cultured HCE-T cells express tight junction protein ZO-1 (green). Nuclei stained with DAPI (blue).
Fig. 1. Cultured HCE-T cells express tight junction protein ZO-1 (green). Nuclei stained with DAPI (blue). 
Fig. 2. Viability of HCE-T cells exposed to 0.001-0.02% of benzalkonium chloride (BAC) measured by the resazurin reduction assay.
Fig. 2. Viability of HCE-T cells exposed to 0.001-0.02% of benzalkonium chloride (BAC) measured by the resazurin reduction assay. 

Authors' picture