Gorbet M B, Tanti N C, Jones L, Sheardown H
Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada.
Mol Vis. 2010 Feb 19;16:272-82.
Although all contact lenses (CLs) are applied initially to the eye directly from a packaging solution, little is known about the effects of these solutions on human corneal epithelial cells (HCECs). Due to the porous nature of CL materials, they have the potential to sorb components of the packaging solution during storage, which could then be subsequently released upon insertion of the CL on the eye. The purpose of this study was to investigate the effect of various packaging solutions on HCECs, using an in vitro model.
An in vitro assay was developed whereby various silicone hydrogels and conventional, poly-2-hydroxyethylmethacrylate (polyHEMA)-based lens materials were removed directly from their packaging and then incubated for up to 24 h with HCECs. The effect of the retained and released packaging solution components on HCECs was assessed by measuring cell viability, adhesion phenotype, and apoptosis.
Incubation of HCECs with CLs stored in borate-buffered packaging solutions resulted in a significant reduction in cell viability. Adherent cells incubated with these CLs also exhibited reduced levels of beta(1) and alpha(3) integrin. Soaking borate-buffered packaged CLs in PBS before cell incubation resolved viability and integrin expression in all cases, with the exception of galyfilcon A and balafilcon A, from which a 20% reduction in cell viability was still observed. In comparison, CLs stored in phosphate-buffered packaging solutions had cellular viability and expression of integrins similar to control cells (cells incubated in the absence of a lens). When incubated with cells at a 10% concentration in serum-free medium, borate-buffered packaging solutions and borate-containing saline (Unisol 4) significantly reduced cell viability and integrin expression. Neither caspase activation nor annexin V binding was observed on cells following exposure to borate buffer solution. However, a significant decrease in reactive oxygen species was observed at 24 h. These latter results suggest that in vitro exposure to low concentration of borate/boric acid results in cell dysfunction, leading to necrosis rather than apoptosis.
Borate-buffered packaging solutions were shown to adversely affect the viability and integrin expression of HCECs in vitro. When used in ophthalmic packaging solutions, the antimicrobial properties of borate buffer may be outweighed by its relatively cytotoxic effects on cells.
尽管所有隐形眼镜（CL）最初都是直接从包装溶液应用于眼睛，但对于这些溶液对人角膜上皮细胞（HCEC）的影响知之甚少。由于CL材料的多孔性质，它们在储存期间有可能吸附包装溶液的成分，然后在将CL插入眼睛时随后释放出来。本研究的目的是使用体外模型研究各种包装溶液对HCEC的影响。
开发了一种体外试验，通过该试验将各种硅水凝胶和传统的基于聚甲基丙烯酸2-羟乙酯（polyHEMA）的镜片材料直接从其包装中取出，然后与HCEC一起孵育长达24小时。通过测量细胞活力、粘附表型和细胞凋亡来评估保留和释放的包装溶液成分对HCEC的影响。
将HCEC与储存在硼酸盐缓冲包装溶液中的CL一起孵育导致细胞活力显著降低。与这些CL一起孵育的贴壁细胞还表现出β(1)和α(3)整合素水平降低。在细胞孵育前将硼酸盐缓冲包装的CL浸泡在PBS中，在所有情况下都能解决细胞活力和整合素表达问题，但加雷菲康A和巴拉菲康A除外，仍观察到细胞活力降低20%。相比之下，储存在磷酸盐缓冲包装溶液中的CL具有与对照细胞（在无镜片情况下孵育的细胞）相似的细胞活力和整合素表达。当在无血清培养基中以10%的浓度与细胞一起孵育时，硼酸盐缓冲包装溶液和含硼酸盐的盐水（Unisol 4）显著降低细胞活力和整合素表达。在暴露于硼酸盐缓冲溶液后，细胞上未观察到半胱天冬酶激活或膜联蛋白V结合。然而，在24小时时观察到活性氧显著减少。后一组结果表明，体外暴露于低浓度的硼酸盐/硼酸会导致细胞功能障碍，导致坏死而非凋亡。
硼酸盐缓冲包装溶液在体外对HCEC的活力和整合素表达有不利影响。当用于眼科包装溶液时，硼酸盐缓冲液的抗菌特性可能被其对细胞的相对细胞毒性作用所抵消。
