High molecular weight hyaluronan decreases UVB-induced apoptosis and inflammation in human epithelial corneal cells

PURPOSE: The aim of this study was to investigate high molecular weight hyaluronan (HMW-HA) protection on human corneal epithelial (HCE) cells against ultraviolet B (UVB) radiation-induced toxic effects. METHODS: The HCE cell line was incubated with HMW-HA or phosphate-buffered salt solution (PBS), rinsed, and exposed to UVB radiation. Cell viability, reactive oxygen species (ROS) and glutathione (GSH) levels, 8-hydroxy-2'-deoxyguanosine (8-oxo-dG) release, p53 phosphorylation, caspase-3, -8, -9 activation, and interleukin (IL)-6 and -8 production were assessed to evaluate and to compare UVB-induced toxicity between cells treated with HMW-HA and cells treated with PBS. RESULTS: Data indicate that HMW-HA had significant protective effects against UVB radiation. HMW-HA increased HCE cell viability, decreased IL-6 and -8 production, and decreased caspase-3 and -8 activation. However, HMW-HA had no significant effect on ROS and GSH levels, 8-oxo-dG release, and p53 phosphorylation. CONCLUSIONS: To our knowledge, we report for the first time the ability of HMW-HA to protect cells against UV irradiation. According to our results, HMW-HA provides anti-inflammatory and anti-apoptotic signals to cells exposed to UVB.