To evaluate the response and cellular damage of cultured human pterygial cells according to the concentration and exposure time of topical cyclosporin.

Human pterygial cells were exposed to a cyclosporin A concentrations of 0.1 µg/ml (0.0001%), 1 µg/ml (0.0001%), 10 µg/ml (0.001%), 100 µg/ml (0.01%), or 500 µg/ml (0.05%) for 5 or 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 damage. The extra-cellular matrix of PIP, laminin and MMP were evaluated, and the measurement of pro-inflammatory cytokine, TNF-α and IL-1b. IL-6, IL-8 was performed using ELISA kits.

The pterygial cellular inhibitory effect of cyclosporin was similar to that of the control according to the concentration and exposure time ( p > 0.05). Compared with the control, the level of LDH did not show a statistically significant difference between concentration and exposure time ( p > 0.05). There was no significant difference of inhibitory effects by PIP, laminin, or MMP between the experimental and control groups ( p > 0.05). The production of TNF-α and IL from the experimental pterygial cells due to the effect of cyclosporin was not significantly different from that of the control at a longer exposure time or stronger concentration ( p > 0.05).

The response of pterygial cells to topical cyclosporin A at concentrations less than 0.05% for less than 10 minutes of exposure time showed no prevention of pterygial recurrence. With regard to cellular damage, little effects on inhibition of PIP, laminin, MMP, IL, and TNF-α were observed compared with that of the control.