Effects of multipurpose care solutions for RGP contact lenses on corneal epithelial tight junctions

Abstract

Purpose: To study the cytotoxicity of RGP contact-lens multipurpose care solutions (RGP-MPSs), the effects of RGP-MPSs on corneal epithelial tight junction were evaluated in vitro. Methods: Five commercial RGP-MPSs (MPS-A: Polylysine (100ppm), MPS-B: PHMB (5ppm), MPS-C: PHMB (5ppm) +Chlorhexidine (30ppm), MPS-D: PHMB (1ppm), MPS-E: Hydrogen peroxide (100ppm) +Oxychlorite) were used in these studies. Human corneal epithelial (HCE-T) cells were exposed to each MPS for5or15min. Tight junction integrityof theHCE-T cellswasevaluatedwith ZO-1 (tight junction-related protein) labeling under laser confocal microscopy. For quantitative evaluation of barrier functions, transepithelial electrical resistance (TER) of the HCE-T cells was also measured 5, 15 and 30min after MPS exposure by using a volt ohmmeter. Results: ZO-1 of HCE-T cells was observed as a continuous linear pattern along with cell–cell borders. Five minutes exposure of each MPS had almost no effects on the ZO-1 integrity except for small-spreading of intercellular spaces in all MPSs. Fifteen minutes exposure of MPS-C, -D and E caused a partially destructed structure of ZO-1 accompanied by wide-spreading intercellular spaces unlike MPS-A and -B keeping almost normal distribution of ZO-1. The initial TER value of HCE-T cells was approximately 300–350 /cm2. TER of the cells treated with each MPS decreased to approximately half of initial value after 5min and to 10% or less after 30min of incubation. Conclusions: These results suggest the possibility that frequent use of a MPS with high cytotoxicity may lead to the breakdown of epithelial barrier functions.