Understanding the effects of ciprofloxacin on corneal epithelial cells: a study using electric cell-substrate impedance sensing (ECIS) technology.

Ciprofloxacin (CPFX) is a widely used ocular antibiotic, but its effects on ocular surface cells remain unclear. Mechanistic investigations into the efficacy of thymosin beta-4 (Tβ4) as an adjunct to CPFX in treating Pseudomonas aeruginosa keratitis revealed off-target effects of the antibiotic. Subsequently, an in vitro approach was used to elucidate the impact of CPFX on corneal epithelial cells, both alone and in combination with Tβ4. Electric cell-substrate impedance sensing (ECIS) was used to directly analyze cell behavior. CPFX demonstrated biphasic effects, characterized by early alterations in impedance (<24 h), followed by significant disruption of the cell monolayer thereafter. Although Tβ4 improved wound healing and barrier function, the disruptive effects of CPFX were not fully mitigated. The negative impact of the antibiotic was concentration-dependent and mirrored by its concentration-dependent toxicity. Western blot analysis demonstrated concentration-dependent alterations in apoptotic signaling that paralleled reductions in cell viability. Collectively, these findings indicate that CPFX exerts concentration-dependent cytotoxic effects accompanied by altered apoptotic signaling on corneal epithelial cells, with early stress-related changes preceding cellular damage. These findings highlight the importance of cautious interpretation of early time points and careful consideration of CPFX use in contexts where epithelial integrity and wound healing are paramount.