Effects of contact lens multipurpose solutions on human corneal epithelial survival and barrier function

Purpose. To examine the effect of 4 commercially available contact lens multipurpose solutions (MPS) on the viability and barrier function Of human corneal epithelial cells in vitro. Methods. Immortalized human corneal epithelial cells were exposed to 4 solutions. MPS A, B, C, and D with Culture medium and Hanks' Balanced Salt Solution as controls. MTT assay was used to evaluate cell viability. ApopTag Fluorescein Apoptosis assay was used to detect cell death in situ. Corneal epithelial barrier function was evaluated by fluorescein permeability and immunofluorescent staining for tight junction proteins zonula occludens (ZO)-1 and occludin. Results. Corneal epithelial survival rates, evaluated by MTT assay showed no statistical difference between MPS A and the Culture medium or Hanks' Balanced Salt Solution controls. MPS B, C, and D were associated with significantly less cell survival than the controls after exposure for 6 hrs (all P<0.01). Compared with the controls. the MPS A did not increase cell apoptosis, whereas the other 3 caused higher apoptotic rates. The epithelial permeability after exposure to MPS A was similar to controls and significantly lower than MPS B and MPS D (P<0.01). The tight junction proteins ZO-1 and occludin were well maintained after exposure to MPS A. In contrast, the expression of ZO-1 and occludin were largely disturbed by the other 3 MPS Solutions. Conclusions. The current marketed contact lens MPS may have negative effects on human corneal epithelial viability and barrier function. Among 4 MPS studied, MPS A maintains the cell viability and barrier function significantly better than other 3 marketed products.