Oroxylin A alleviates pyroptosis and apoptosis in human corneal epithelial cells under hyperosmotic stress by activating the SIRT3-SOD2/HIF-1α pathway.

Dry eye disease (DED) is a common ocular surface problem. Ocular surface inflammation and oxidative stress triggered by increased tear osmolarity are crucial pathogeneses of DED. Oroxylin A (OA) extracted from Scutellaria baicalensis exhibits anti-inflammatory, antioxidant, and cell protective properties. The aim of this study was to determine the protective effect and explore the potential mechanisms of OA on hyperosmotic stress-induced human corneal epithelial cells (HCECs). In this study, we demonstrated that OA exhibited a marked protective effect on hyperosmolarity-induced HCEC damage, including improving cell viability and decreasing lactate dehydrogenase release. Furthermore, OA reduced the expression of proinflammatory cytokines (IL-6, IL-1β, and TNF-α) and the generation of oxidative stress-related markers (ROS and NO) in hyperosmotic stress-induced HCECs. In addition, OA decreased HCEC pyroptosis by decreasing NLRP3, caspase-1, cleaved-caspase-1, and N-GSDMD levels. OA also decreased HCEC apoptosis by enhancing Bcl-2 expression while simultaneously decreasing caspase-3 and Bax levels. Moreover, OA enhanced SIRT3 expression in hyperosmotic stress-induced HCECs. A SIRT3 inhibitor reversed the alleviation of pyroptosis and apoptosis induced by OA. SIRT3 could promote SOD2 expression and inhibit HIF-1α and ROS expression in hyperosmotic stress-induced HCECs. In conclusion, OA exhibits anti-inflammatory and antioxidant properties and can alleviate the pyroptosis and apoptosis of HCECs under hyperosmotic stimulation by activating the SIRT3-SOD2/HIF-1α signaling pathway. Therefore, OA may be a new treatment target for dry eye disease.