KRT5 and ulcer disease: H&E staining and immunofluorescence staining of CK 5 and CK 13 were performed to evaluate the inflammation and epithelium recovery, wherein CK 5 targeted the surface layer and CK 13 stained the intermediate layer, respectively.[18, 20, 41] The broken ulcer with a disordered orientation in the epithelium verifies the successful construction of the OM model (Figure 5g).