Cytokeratins of the matrices of the chestnut (torus carpeus) and periople in horses with acute laminitis.
OBJECTIVE
To determine whether there is a change in the expression of cytokeratins in the epidermal cells of the non-weight-bearing parts of the limb in horses with acute laminitis and thus determine whether the morphologic changes that develop in the periople and chestnut (torus carpeus) of horses early in acute laminitis are caused by inhibition of keratinocyte differentiation.


METHODS
8 horses with acute laminitis.


METHODS
Tissue specimens were obtained from the chestnuts of all 8 horses and from the stratum externum of the hoof wall of 3 horses. Tissue specimens were obtained within 48 hours of the first clinical signs of laminitis. The cytokeratins were characterized by 1- and 2-dimensional gel electrophoresis, and the tissue distribution of the cytokeratins was studied by immunohistochemical staining.


RESULTS
The biochemical findings indicated that the epidermal cells of tissues from horses affected by laminitis contained the same set of cytokeratins as corresponding tissues from clinically normal horses. Immunohistochemistry on sections from specimens of horses with laminitis versus clinically normal horses indicated a difference in the expression of cytokeratin in the basal cells in the matrix of the stratum externum of the hoof wall and in the matrix of the chestnut of horses with laminitis in which the most severe morphologic changes were observed.


CONCLUSIONS
Inhibition of keratinocyte differentiation, as observed by immunohistochemical changes, in cells in parts of the chestnut and periople may indirectly indicate that the observed epidermal changes in horses with laminitis are primary and are unaffected by weight-bearing.
Department of Large Animal Clinical Sciences, Faculty of Veterinary Medicine, University of Agricultural Sciences, Uppsala, Sweden.
O S
OS
Wattle
D000208:Acute Disease; D000818:Animals; D002454:Cell Differentiation; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004817:Epidermis / Q000378:metabolism / Q000473:pathology; D005260:Female; D005534:Foot Diseases / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D006724:Hoof and Claw / Q000378:metabolism* / Q000473:pathology; D006734:Horse Diseases / Q000378:metabolism* / Q000473:pathology; D006736:Horses; D007150:Immunohistochemistry / Q000662:veterinary; D015603:Keratinocytes / Q000473:pathology; D007633:Keratins / Q000096:biosynthesis* / Q000302:isolation & purification; D007794:Lameness, Animal / Q000209:etiology / Q000378:metabolism; D008297:Male
D007633:Keratins