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Discussion on Research Summary: Possible cause of black walnut associated founder
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Moderator:
DrO
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Posted on Wednesday, Apr 18, 2007 - 10:07 am:
Though we know horses exposed to enough black walnut plant parts develop founder a mechanism has eluded us. This study implicates that inflammation induced by migrating white blood cells into the laminae may be the primary event in black walnut induced founder.
DrO
Am J Vet Res. 2007 Jan;68(1):81-6.
Neutrophil myeloperoxidase measurements in plasma, laminar tissue, and skin of horses given black walnut extract.
Riggs LM, Franck T, Moore JN, Krunkosky TM, Hurley DJ, Peroni JF, de la Rebiere G, Serteyn DA.
Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
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). ANIMALS: 22 healthy 5- to 15-year-old horses. PROCEDURES: 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. 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 AND CLINICAL RELEVANCE: 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.
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