Figure 1. The corneal rims were divided into five parts (A to E). Part A was used for immunofluorescence staining. Part B was stained with trypan blue and alizarin red. The endothelium from part C was stripped away intact and frozen at −80 °C for RNA analysis. Part D and part E were used for the immunohistochemical staining of p16^INK4a and Bmi1, respectively.