Cytokeratins of the equine hoof wall, chestnut and skin: bio- and immunohisto-chemistry.

The equine skin and its appendages (chestnut, hoof capsule, ergot, sebaceous glands, sweat glands and hair) consist mainly of keratinocytes. The intermediate filament cytoskeleton of these cells in involved in specialised functions, such as mechanical co-ordination of the cytoskeleton of the cell or tissue. In this study, 7 monoclonal antibodies, one polyclonal antibody and immunoblot analysis were used to characterise cytokeratins (separated by 1- and 2-dimensional gel electrophoresis) from the hoof wall and chestnut. The tissue distribution of these cytokeratins was studied by immunohistochemical staining of sections from the skin, chestnut, periople, matrix of the stratum medium of the hoof wall, and the stratum internum of the hoof wall. The results of analysis revealed a difference in the content of cytokeratins between: 1) cell layers within the same tissue, 2) skin and more proliferative epidermal tissues, i.e., chestnut and periople, 3) tissues containing a stratum granulosum (skin, chestnut and periople) and tissues without stratum granulosum (stratum medium and internum of the hoof wall), 4) stratum medium and stratum internum of the hoof wall and 5) stratum internum at the most proximal level and at the mid level of the hoof wall.