To evaluate the response and cellular changes of cultured human corneal epithelium according to the concentration of topical cyclosporine.

Human corneal epithelial cells were exposed to cyclosporine A concentrations of 1 ug/ml (0.0001%), 10 ug/ml (0.001%), 100 ug/ml (0.01%), and 500 ug/ml (0.05%) for 5 and 10 minutes. An MTT-based colorimetric assay was performed to assess the metabolic activity of cellular proliferation and a lactate dehydrogenase (LDH) leakage assay was used to determine cellular toxicity. The modulations of extracellular matrix proteins such as PIP and laminin were evaluated. The levels of pro-inflammatory cytokine, TNF-α, and IL-1 were evaluated by ELISA kits.

The inhibitory effects of human corneal epithelial cellular proliferation did not show a concentration- or exposure time-dependent response. Activity of LDH did not show a statistically significant difference for the different concentrations and exposure times. The inhibitory effects of extracellular matrix proteins such as PIP or laminin synthesized from human corneal epithelial cells were compared with those in the control group and showed a statistically significant difference at a cyclosporine concentration greater than 0.01%. Released TNF-α and IL-1 from human corneal epithelial cells did not show any difference according to concentration or cyclosporine exposure time.

To modulate human corneal epithelial cellular proliferation and the levels of extracellular matrix proteins such as PIP and laminin, a concentration of cyclosporine A greater than 0.01% for longer than 5 minutes of exposure is needed. There were little effects of cyclosporine A on pro-inflammatory cytokine secreted from corneal epithelial cells.