School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada.
Centre for Ocular Research & Education, School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada.
Cutan Ocul Toxicol. 2020 Dec;39(4):370-379. doi: 10.1080/15569527.2020.1833027. Epub 2020 Nov 3.
To investigate the combined toxic effect of ultraviolet (UV) radiation and benzalkonium chloride (BAK), a common preservative in ophthalmic eye drops, on human corneal epithelial cells (HCEC).
Cultured HCEC were exposed to different combined and separate UV (280-400 nm) and BAK solutions at relevant human exposure levels. Human exposure to UV can occur before, during, or after eye drop installation, therefore, three different orders of ocular exposures were investigated: UV and BAK at the same time, UV first followed by BAK, and BAK first followed by UV. Control treatments included testing HCEC exposed to BAK alone and also HCEC exposed to UV alone. In addition, phosphate-buffered saline (PBS) was used as a negative control. After exposure, cell metabolic activity of the cultures was measured with PrestoBlue, and cell viability was determined using confocal microscopy with viability dyes.
BAK alone reduced the metabolic activity and cell viability of HCEC in a dose- and time-dependent manner. UV alone at a low dose (0.17 J/cm) had little toxicity on HCEC and was not significantly different from PBS control. However, UV plus BAK showed combined effects that were either greater than (synergistic) or equal to (additive) the sum of their individual effects. The synergistic effects occurred between low dose UV radiation (0.17 J/cm) and low concentrations of BAK (0.001%, 0.002%, 0.003%, and 0.004%).
This investigation determined that at relevant human exposure levels, the combination of UV radiation (280-400 nm) and BAK can cause synergistic and additive toxic effects on human corneal epithelial cells. This finding highlights the importance of considering the combined ocular toxicity of BAK and solar radiation in the risk assessment of BAK-preserved ophthalmic solutions.
研究紫外线（UV）辐射和苯扎氯铵（BAK），一种常见的眼科滴眼液防腐剂，对人角膜上皮细胞（HCEC）的联合毒性作用。
将培养的 HCEC 暴露于不同的组合和单独的 UV（280-400nm）和 BAK 溶液中，达到相关的人体暴露水平。人眼在滴眼药水之前、期间或之后都可能暴露于 UV 下，因此，研究了三种不同的眼部暴露顺序：UV 和 BAK 同时暴露，UV 先暴露然后 BAK 暴露，以及 BAK 先暴露然后 UV 暴露。对照处理包括单独测试 BAK 暴露的 HCEC 和单独测试 UV 暴露的 HCEC。此外，磷酸盐缓冲盐水（PBS）用作阴性对照。暴露后，使用 PrestoBlue 测量培养物的细胞代谢活性，并使用活细胞染料通过共聚焦显微镜确定细胞活力。
BAK 单独作用于 HCEC 呈剂量和时间依赖性降低细胞代谢活性和细胞活力。低剂量（0.17J/cm）的 UV 单独作用对 HCEC 的毒性较小，与 PBS 对照无显著差异。然而，UV 加 BAK 表现出协同作用或相加作用，大于或等于其各自的作用之和。协同作用发生在低剂量 UV 辐射（0.17J/cm）和低浓度 BAK（0.001%、0.002%、0.003%和 0.004%）之间。
本研究确定，在相关人体暴露水平下，UV 辐射（280-400nm）和 BAK 的组合对人角膜上皮细胞可引起协同和相加的毒性作用。这一发现强调了在评估 BAK 保存的眼科溶液的风险时，考虑 BAK 和太阳辐射联合眼部毒性的重要性。
