Corneal sections and cultured cells were fixed with 4% paraformaldehyde for 10 minutes at room temperature. After permeabilization, all samples were blocked with 5% BSA (Solarbio, Beijing, China) and incubated with the primary antibodies of Ki67, vimentin, P16Ink4a (P16), α-SMA, CD45, CD11b, P21Cip1 (P21), γH2A.X (phospho S139), collagen I (COL I), and fibronectin (FN) (Abcam, Cambridge, UK) at 4°C overnight; they were then washed and incubated with donkey Alexa Fluor 488– or 594–conjugated secondary antibodies (Invitrogen, Carlsbad, CA, USA) for 1.5 hours at room temperature and washed again with PBS. For F-actin staining, the cultured cells were fixed, permeabilized, and stained with FITC-conjugated phalloidin (Molecular Probes, Carlsbad, CA, USA). All staining was examined under a Nikon fluorescence microscope. TUNEL+, Ki67+, and SA-β-gal+ cells within the corneal stroma were counted in five to seven serial sections from each cornea using ImageJ software (National Institutes of Health, Bethesda, MD, USA). At least three corneas per group were analyzed.