Recombinant human epithelial growth factor

Damage caused by ultraviolet radiation is an important factor in corneal injury.^{26 (link)} HCECs (CP-H128; Procell, Austin, TX, USA) were grown in DMEM/F12 medium (Invitrogen, Carlsbad, CA, USA) containing 6% fetal bovine serum (FBS; Sigma-Aldrich, St. Louis, MO, USA), 7 g/mL fetal bovine insulin (Sigma-Aldrich), and 7 ng/mL recombinant human epithelial growth factor (Sigma- Aldrich) at 37°C in a 5% CO^{2 (link)} atmosphere. After referring to relevant literature,^{27 (link)} HCECs were exposed to UV light (5.73 W/m^{2 (link)}) at a distance of 30 cm for 5 min at 37°C in a 5% CO^{2 (link)} atmosphere in a special apparatus. The UV intensity used for the control group was 0.1719 J/cm². An miR-18 inhibitor, negative control (NC), and miR-18a mimics were purchased from GenePharma (Suzhou, China). HCECs were seeded into the wells of a 6-well plate (1 . 10⁵ cells/well). The cells were then treated with SH and transfected for 48 h with miR-18a mimics by using Lipofectamine 3000 (Invitrogen) as described in the manufacturer’s instructions.