Sodium hyaluronate promotes proliferation, autophagy, and migration of corneal epithelial cells by downregulating miR-18a in the course of corneal epithelial injury

Corneal epithelium can resist the invasion of external pathogenic factors to protect the eye from external pathogens. Sodium hyaluronate (SH) has been confirmed to promote corneal epithelial wound healing. However, the mechanism by which SH protects against corneal epithelial injury (CEI) is not fully understood. CEI model mice were made by scratching the mouse corneal epithelium, and in vitro model of CEI were constructed via curettage of corneal epithelium or ultraviolet radiation. The pathologic structure and level of connective tissue growth factor (CTGF) expression were confirmed by hematoxylin and eosin staining and immunohistochemistry. CTGF expression was detected by an immunohistochemistry assay. The levels of CTGF, TGF-β, Col1A1, FN, LC3B, Beclin1, and P62 expression were monitored by RT-qPCR, ELISA, Western blotting or immunofluorescence. Cell proliferation was detected by the CCK-8 assay and EdU staining. Our results showed that SH could markedly upregulate CTGF expression and downregulate miR-18a expression in the CEI model mice. Additionally, SH could attenuate corneal epithelial tissue injury, and enhance the cell proliferation and autophagy pathways in the CEI model mice. Meanwhile, overexpression of miR-18a reversed the effect of SH on cell proliferation and autophagy in CEI model mice. Moreover, our data showed that SH could induce the proliferation, autophagy, and migration of CEI model cells by downregulating miR-18a. Down-regulation of miR-18a plays a significant role in the ability of SH to promote corneal epithelial wound healing. Our results provide a theoretical basis for targeting miR-18a to promote corneal wound healing.