Expression of NTN-1 derived by corneal epithelium decreases in DED mice. (A) Heatmap identified differentially expressed neural factors in corneal epithelium of DED mice and normal mice detected using RNA-seq. (B) The mRNA levels of NTN-1 by the corneal epithelial were quantified using real-time PCR (corneal epithelium was collected on day 3 or day 5 post-DED induction; the corneal epithelium of four eyes was pooled together as a sample, n = 5). (C, D) The protein levels of NTN-1 in the corneal epithelium were evaluated by Western blot, with GAPDH as the internal control (corneal epithelium was collected on day 5 after DED induction; the corneal epithelium of four eyes was pooled together as a sample, n = 3). (E) Representative images of corneal NTN-1 immunofluorescence staining. Three independent experiments were pooled in the statistical analysis. Data are shown as mean ± SEM. **P < 0.01, ***P < 0.001. ns, no significance.