Submural histopathologic changes attributable to peracute laminitis in horses.
OBJECTIVE
To describe submural histopathologic changes attributable to peracute laminitis in horses.


METHODS
20 adult horses.


METHODS
A concurrent-control design was used to compare laminar lesions in 10 horses subjected to carbohydrate-induced laminitis with laminar characteristics of 10 sex- and aged-matched control horses with normal feet. Horses in the treatment group were administered an overload of carbohydrate. Tissues were obtained by biopsy 4 to 8 hours after onset of lameness or 72 hours after administration of the carbohydrate overload when lameness did not develop. Sections were stained with H&E, Masson's trichrome, and periodic acid-Schiff stains. Histopathologic changes were analyzed to detect differences between groups and to correlate epidermal changes with severity and duration of lameness.


RESULTS
Analysis indicated that dermal and epidermal lesions were evident despite lack of visible separation of the epidermal basement membrane, can be found in horses without detectable lameness, and were nonspecific and progressive following onset of lameness. Furthermore, severity and location of lesions were associated with severity and duration of lameness.


CONCLUSIONS
These observations are consistent with the concept that separation of the laminar epithelial basement membrane is a delayed step in the pathogenesis of acute laminitis, digital vascular hypoperfusion is an underlying cause for laminitis, and the potential for repeated episodes of subclinical laminitis may underlie the development of structural and mechanical changes consistent with chronic laminitis despite lack of clinical signs of acute laminitis.
Morgan
Sherry J
SJ
Department of Pathology, Abbott Laboratories, Abbott Park, IL 60064, USA.
Hood
David M
DM
Wagner
Ilka P
IP
Postl
Steve P
SP
D000818:Animals; D002241:Carbohydrates / Q000494:pharmacology; D005534:Foot Diseases / Q000139:chemically induced / Q000473:pathology* / Q000662:veterinary*; D006724:Hoof and Claw / Q000187:drug effects / Q000473:pathology*; D006734:Horse Diseases / Q000139:chemically induced / Q000473:pathology*; D006736:Horses
D002241:Carbohydrates