Purchase this article with an account.
Hong Liang, Christophe Baudouin, Philippe Daull, Jean-Sebastien Garrigue, Francoise Brignole-Baudouin; Hyperosmolar conditions Increase benzalkonium chloride (BAK) toxicity in an in vitro cornea wound healing model and an in vivo dry eye mouse model. Invest. Ophthalmol. Vis. Sci. 2013;54(15):6041.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Cytotoxic effects of benzalkonium chloride (BAK) were reported to increase in hyperosmolar conditions (HO) on conjunctival epithelial cells in vitro with the characteristics of apoptosis and oxidative stress. In order to better understand the influences of HO and BAK on the ocular surface, we tested these two conditions in a corneal wound healing assay using human corneal epithelial cells (HCE) (1), and in a mouse model of dry eye (2).
(1) A wound was established by scraping manually through a confluent HCE layer. Cytotoxicity, cell migration, and proliferation were analyzed after a 30mn-exposure to phosphate-buffered saline (PBS, negative control), 0.02%BAK in normal (275mOsm/L) and in three different hyperosmolar conditions: 356-406-505mOsm/L. Immunohistology was performed for F-actin cytoskeleton and proliferation marker Ki-67. (2) A dry eye model was induced in mice by topical administration twice a day (D) for 5D of 0.2%BAK and 0.1%BAK in 275mOsm/L solution and in HO (505mOsm/L). We evaluated the ocular surface using Phenol red thread tear- (PRT), tear break-up time- (BUT), fluorescein- tests and in vivo confocal microscopy (IVCM). Immunohistology was performed to assess MUC5AC and CD45-positive cells.
(1) Corneal healing was delayed in 0.02%BAK, this delay increasing in a HO-dependent manner with a F-actin disorganization and a decrease of Ki-67+ cells. (2) 0.1%BAK in normal osmolar conditions did not induce any dry eye sign while in HO, it decreased PRT and BUTs and increased corneal fluorescein scores. By IVCM, we found inflammatory cell infiltrations in the cornea. Immunohistology revealed the loss of MUC5AC+ cells with an increase of CD45+ inflammatory cells in hyperosmolar 0.1%BAC-treated mouse conjunctival fornix.
These in vivo and in vitro studies, showed the impacts on the ocular surface of the association of two different stresses that could be commonly found in glaucoma patients treated with preserved eyedrops, hyperosmolar conditions and BAK. Hyperosmolarity induced by BAK, potentiatess in turn BAK toxicity, thus impairing the corneal healing process and the dry eye conditions. This study highlights once more the importance of avoiding BAK in long-term treated patients and in patients with an ocular surface disease.
This PDF is available to Subscribers Only