Comparison of cytotoxicity and wound healing effect of carboxymethylcellulose and hyaluronic acid on human corneal epithelial cells

AIM: To investigate the cytotoxic effect on human corneal epithelial cells(HCECs) and the ability to faciliate corneal epithelial wound healing of carboxymethylcellulose(CMC) and hyaluronic acid(HA).METHODS: HCECs were exposed to 0.5% CMC(Refresh plus, Allergan, Irvine, California, USA) and 0.1% and 0.3%HA(Kynex , Alcon, Seoul, Korea, and Hyalein mini,Santen, Osaka, Japan) for the period of 30 min, and 4, 12,and 24 h. Methyl thiazolyl tetrazoiun(MTT)-based calorimetric assay was performed to assess the metabolic activity of cellular proliferation and lactate dehydrogenase(LDH) leakage assay to assess the cytotoxicity. apoptotic response was evaluated with flow cytometric analysis and fluorescence staining with Annexin V and propiodium iodide. Cellular morphology was evaluated by inverted phase-contrast light microscopy and electron microscopy. The wound widths were measured 24 h after confluent HCECs were scratch wounded.RESULTS: The inhibitory effect of human corneal epithelial proliferation and cytotoxicity showed the time-dependent response but no significant effect. Apoptosis developed in flow cytometry and apoptotic cells weredemonstrated in fluorescent micrograph. The damaged HCECs were detached from the bottom of the dish and showed the well-developed vacuole formations. Both CMC and HA stimulated reepithehlialization of HCECs scratched, which were more observed in CMC.CONCLUSION: CMC and HA, used in artificial tear formulation, could be utilized without any significant toxic effect on HCECs. Both significantly stimulated HCEC reepithelialization of corneal wounds.