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Graefes Arch Clin Exp Ophthalmol. 2011 Nov;249(11):1681-7. doi: 10.1007/s00417-011-1755-0. Epub 2011 Aug 13.

Role of benzalkonium chloride in DNA strand breaks in human corneal epithelial cells.

Author information

1
Department of Ophthalmology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, China. yejuan@zju.edu.cn

Abstract

PURPOSE:

To investigate the toxic effects of benzalkonium chloride (BAC), a preservative commonly used in ophthalmic preparations, on DNA single- and double-strand breaks in immortalized human corneal epithelial cells (HCEs).

METHODS:

HCEs were treated with BAC in concentrations ranging from 0.00005% to 0.001% for 30 min. Cells were examined immediately after BAC exposure and after 24-h recovery. Alkaline comet assay was used to detect DNA single-strand breaks (SSBs). Immunofluorescence microscope detection of the phosphorylated form of histone variant H2AX (γH2AX) foci indicated DNA double-strand breaks (DSBs). Cell viability was measured by the MTT test.

RESULTS:

A significant increase of SSBs, detected by alkaline comet assay, was observed in a dose-dependent manner with BAC exposure in HCEs at concentrations of 0.00005% and higher. Such BAC treatment also exhibited a dose-dependent increase in DSBs, evaluated by number of γH2AX foci. In addition, a significant change in the relative cell survival rate of HCEs was observed after exposure to 0.001% BAC for 30 min. Although the toxic effects of BAC could be partly repaired after 24 h of cell recovery, SSBs and DSBs in HCEs were still present after BAC removal.

CONCLUSIONS:

The results demonstrated that exposure to BAC in HCEs, even at low concentrations, could induce DNA strand breaks, which were present after BAC removal. Cell survival analysis indicated that BAC-induced DNA damage was correlated with the cytotoxic effects.

PMID:
21842132
DOI:
10.1007/s00417-011-1755-0
[Indexed for MEDLINE]

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