Histologic Morphology and Involucrin, Filaggrin, and Keratin Expression in Normal Canine Skin from Dogs of Different Breeds and Coat Types

This study investigated the thickness of canine epidermis and the expression of cornified envelopes and keratins in the skin of five dog breeds: poodles, golden retrievers, Shih Tzus, pugs, and Labrador retrievers. It found significant differences in epidermal thickness across different anatomical sites and breeds, with the thickest skin in the digital web area and the thinnest in the axilla. Immunohistochemical staining showed decreased levels of involucrin, filaggrin, and keratin 10 in ventral and weight-bearing sites, while keratin 5 increased. mRNA levels were positively correlated with protein expression. This was the first study to report the relationship between epidermal gene expression and skin morphology in normal dogs, suggesting the need for further research on canine skin barrier dysfunctions.