[Effects of benzalkonium chloride on MUC1 in human conjunctival epithelial cells]

To investigate the effects of benzalkonium chloride (BAC), a preservative used in many ophthalmic topical solutions, on mucin1 (MUC1) in human conjunctival epithelial cells in vitro.

Cultured epithelial cells obtained from human conjunctiva were exposed to medium containing BAC solutions at 0.0100%, 0.0050%, 0.0010%, 0.0005% and 0.0001% concentrations for a period of 15 min. Cells were examined after treatment and 6, 12, 24, 48 and 72 h later. The relative expression of the MUC1 mucin gene was determined by conventional reverse transcription-polymerase chain reaction (RT-PCR). Monoclonal antibody for MUC1 was used in Western blot analysis to detect MUC1.

Cell exposure to 0.0100% and 0.0050% BAC decreased the expression of MUC1 at gene level between 12 and 72 h after treatment. Cells treated with 0.0010% and 0.0005% BAC decreased the expression of MUC1 between 24 and 48 h after treatment, recovered 72 h after treatment. At protein level, cells exposed to 0.0100% BAC decreased MUC1 between 24 and 72 h, 0.0050% BAC between 12 and 72 h, 0.0010% BAC 72 h later.

These results suggest that BAC induces decreased expression of MUC1 at both gene and protein levels. The mode of BAC-induced decreased expression of MUC1 is dose-dependent.