Evaluation of Moxifloxacin-induced Cytotoxicity on Human Corneal Endothelial Cells

Moxifloxacin hydrochloride (MXF) is widely used for the prevention of bacterial endophthalmitis after intraocular surgeries. However, the safety issue of intracameral injection of MXF for human corneal endothelial cells (HCECs) is still debatable. In this study, we investigated concentration-dependent cytotoxicity (0.05-1 mg/ml) of MXF for immortalized HCECs (B4G12 cell) and the underlying mechanism. Reactive oxygen generation (ROS) and cell viability after MXF exposure was measured. Flow cytometric analysis and TUNEL assay was used to detect apoptotic HCECs after MXF exposure. Ultrastructure of damaged HCECs by MXF was imaged by transmission electron microscope. Western blot analysis and caspase 2, 3 and 8 analysis were used to reveal the underlying mechanism of MXF induced damage in HCECs. We found that MXF induced dose-dependent cytotoxicity in HCECs. MXF exposure increased ROS generation and induced autophagy in HCECs. Increased LDH release represented the cellular membrane damage by MXF. In addition, caspases activation, Bax/Bcl-xL-dependent apoptosis pathway and apoptosis inducing factor nuclear translocation were all involved in MXF induced HCECs' damage, especially after exposure to high dose of MXF (0.5 and 1.0 mg/ml). These findings suggest that MXF toxicity on HCECs should be thoroughly considered by ophthalmologists when intracameral injection of MXF is planned.