Neutrophil myeloperoxidase measurements in plasma, laminar tissue, and skin of horses given black walnut extract.
OBJECTIVE
To compare measurements of myeloperoxidase (MPO) in plasma, laminar tissues, and skin obtained from control horses and horses given black walnut heartwood extract (BWHE).


METHODS
22 healthy 5- to 15-year-old horses.


METHODS
Horses were randomly assigned to 4 groups as follows: a control group given water (n = 5) and 3 experimental groups given BWHE (17) via nasogastric intubation. Experimental groups consisted of 5, 6, and 6 horses that received BWHE and were euthanatized at 1.5, 3, and 12 hours after intubation, respectively. Control horses were euthanatized at 12 hours after intubation. Plasma samples were obtained hourly for all horses. Laminar tissue and skin from the middle region of the neck were harvested at the time of euthanasia. Plasma and tissue MPO concentrations were determined via an ELISA; tissue MPO activity was measured by use of specific immunologic extraction followed by enzymatic detection.


RESULTS
Tissues and plasma of horses receiving BWHE contained significantly higher concentrations of MPO beginning at hour 3. Laminar tissue and skin from horses in experimental groups contained significantly higher MPO activity than tissues from control horses. Concentrations and activities of MPO in skin and laminar tissues were similar over time.


CONCLUSIONS
In horses, BWHE administration causes increases in MPO concentration and activity in laminar tissue and skin and the time of increased MPO concentration correlates with emigration of WBCs from the vasculature. These findings support the hypothesis that activation of peripheral WBCs is an early step in the pathogenesis of acute laminitis.
Riggs
Laura M
LM
Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
Franck
Thierry
T
Moore
James N
JN
Krunkosky
Thomas M
TM
Hurley
David J
DJ
Peroni
John F
JF
de la Rebière
Geoffroy
G
Serteyn
Didier A
DA
D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005534:Foot Diseases / Q000097:blood / Q000201:enzymology / Q000662:veterinary*; D005552:Forelimb; D006734:Horse Diseases / Q000097:blood / Q000201:enzymology*; D006736:Horses; D031324:Juglans / Q000737:chemistry; D016014:Linear Models; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D009195:Peroxidase / Q000097:blood / Q000378:metabolism*; D010936:Plant Extracts / Q000494:pharmacology; D011897:Random Allocation; D012867:Skin / Q000187:drug effects / Q000201:enzymology
D010936:Plant Extracts; D009195:Peroxidase